EDIT:
Several people have commented that the coworkers can't change, are too stubborn, are undeserving, etc. I conceived of Option 2 after already posting my original answer, but didn't feel it was necessary to update. However, I believe that Option 2 is superior in every way, and would be a positive demonstration of the "Growth Mindset". On the other hand, it does require a certain amount of flexibility on the part of the employer. OP must use judgment to decide whether it is worth pursuing this strategy given the business climate surrounding the organization.
Option 1
$200 can buy an entry-level monitor, and $400 should get a decent mid-range display. Just tell your boss that the company should "save up" for a few months and spend the $200 bonus on new monitors for your whole team. Obviously, the company is being insanely short-sighted and stupid for not doing this math on its own.
As far as the incentive program goes, it should be designed in a way that lets everyone win. One way to do this would be to offer a flat bonus per drawing over the daily quota. If the company estimates that on average, drafters will draw 1 additional drawing a day due to the $200 incentive, and you have 4 folks on your team, then they should offer $10/drawing over quota (computed weekly, of course). If this means that folks suddenly improve their productivity and cause the incentive to exceed $200/week, then that's a problem they should be very glad to have (as presumably, the increased throughput improves their top line by much more than $200/week).
You should also ask your boss to give you a promotion (raise, title, etc.) to "Lead Drafter", "Senior Drafter" or whatever is appropriate, because you are obviously performing at a much higher level than your peers. At that point, you should get higher compensation regardless of the bonus structure because you took the incentive to improve your productivity well beyond your coworkers (who are the strongest witnesses to this fact, being "hostile witnesses"). This would be the company's way of rewarding such employees who improve business productivity on their own.
Furthermore, a promotion would give you authority/cover to spread your techniques to the rest of the team, as the new best practice/business-as-usual, to help them improve as well. This should eliminate any claims of "cheating" or "unfairness". Any boss who pushes back on these ideas is pretty clueless and likely to hamper your career progression. So either they will get on board, or you will have to decide whether to stay in your dead-end job or find a smarter boss. Good luck!
Option 2
Call a 1-on-1 with your boss, and offer this deal:
First, you're going to upgrade the workstations of everyone on the team in the way I have upgraded mine, because I've already demonstrated that it increases productivity. You will take credit for this idea when putting in the hardware request and justifying it to your boss. You will point to my increased productivity as proof that this investment has substantial and quickly-realized ROI.
Second, you will give me 1 month to improve team throughput by 10% (insert realistic value here). After the first month, the team will maintain this higher throughput for 2 more months. After the 3 month demonstration period, you will give the entire team a 10% raise (matching the value above). You will announce this plan to the team in a meeting and obtain their buy-in through your superior management skills, including the rather obvious statement that nobody else in the company is in line for a <10%> raise any time soon.
Third, at the end of the demonstration period you will promote me to Lead Drafter along with a 15-20% raise (make a judgment call here), for permanently improving team performance by <10%>. You will sell this plan upwards as a much better replacement of the ill-conceived bonus plan, which has already generated considerable friction and controversy.
Fourth, you will meet with your manager and sell your considerable influence in improving team morale and performance to leverage a raise/promotion for yourself.
In the unlikely event that I fail to meet the stated goal, the team will keep the improved workstations, which will still pay for themselves quickly, but you are no longer under any other obligations. Is that fair?
Some people will object that the company will not give away 100% of their profit as raises. However, anyone who has been in management will know that wages are not 100% of an employee cost (more like 60-70%). If a team has 10 members, then a 10% throughput increase is about the labor equivalent to hiring another head. But the cost of hiring another head is more like a 15% increase, rather than 10%. This is why companies generally try to squeeze the maximum production out of each employee. The PTO, health insurance, and other benefits are fixed expenses, so the marginal value of additional labor/output is fairly high.
Or, to put it in simple and blunt terms: a 10% improvement for a team of 10 people is worth much more than an additional employee. It's more like a 15% improvement to the company because of better amortization of the fixed costs. So giving a 10% raise still leaves a "free" 5% profit to the company, just for some cheap hardware and better working processes. You should not need to explain this to your boss, but if they are particularly clueless, then, by all means, clue them in.
Of course, many commenters here will object that the coworkers will refuse to participate in this plan, even with the prospect of a 10% raise. I find this difficult to believe. Yes, some people will certainly be more resistant/skeptical of this plan than others. But most folks will respond to strong, positive reinforcement, especially if it is offered as a team incentive. You only need a majority of the team to agree that this is a good plan, because then you co-opt the believers into peer-pressuring the few hold-outs, given that the win is all-or-nothing. You could phrase the plan on an individual basis, but I think that would be a huge mistake. If only 1 or two people take you up on your offer, you may eventually win over the rest of the team, but it makes the whole bargain far less effective/impactful.
Frankly, the whole team should be grateful for such an opportunity, because not only does it offer a chance of a near-guaranteed raise, negotiated for them (the company would surely do better if each team member tried to negotiate a raise personally); but it also improves their skills and value in the marketplace, assuming they weren't planning on retiring at the current company. Plus, it should always be more satisfying working with better equipment, in any case.