If we exclude all other aspects like social standing, professional expertise level and professional versatility (how easy is it to switch from one area of your profession to another), and just focus on the financial life-time income assuming you stay in the same line of work and provide adequate quality, then it is very likely not worth it - but it still might be.
Very likely not worth it because:
- You have a job currently and do it apparently well enough to stay employed (for other readers: this is crucial! A college degree can make getting that first job a lot easier.)
- Let's assume you keep doing the same kind of developer jobs over your lifetime
- Then your industry experience will be enough to get you the next, a degree would barely make a dent upwards in the likelihood to get a follow-up job
- You will likely have to switch the programming language at least once in your life time along with the tool kit, but assuming your tasks otherwise stay the same, that change is manageable. I.e. you can learn the other tools gradually and/or will likely be able to transfer some general knowledge in how they work
it might be worthwhile because:
- a college education gives you a broad foundation which helps to allow/adjust to bigger changes
- 1) say in a few years a lot less developers of your type are needed, perhaps they are automated away. You might need to completely re-adjust and convince employers that you can work in that other domain with that other tool-stack in a short time. Your broad college foundation can help with that.
- 2) if you do not want to keep doing the same, but want to move up or side-ways, e.g. becoming a software architect or data analyst, the same applies
- you can still achieve either of this without a college education, but it can be a lot harder: because you actually have the foundation and because you can prove it. So the college education provides an increased chance to switch to a more profitable line of work or prevent joblessness should you not find a follow-up job fitting your current role. It's a bit like an insurance in that aspect, albeit, it does not give you a guarantee either.
- such a foundation might also make it easier to move up the hierarchy, when you are about to reach (technical) team lead or CTO level
Bottom Line: Without a college degree you will likely not earn significantly less over your lifetime than if you now invest the time and money in said education, calculating that in, you might actually earn about that amount more (probably a bit less, as you might secure a bit higher income with a degree and/or move faster up).
BUT: you will be less flexible in choosing your path, which translates to a certain income gap risk later in life when you need to re-educate yourself.
Going for a college degree, you will certainly loose the time and money you'd spend in the college education. There is some chance that the college education does open you routes that would allow you to gain significantly more, but that chance is small (it's still larger than the chance that not pursuing a college education opens you a route that would make you significantly more than if you'd go with the college education - aside from the money and time spent to get the education in the first place). The main difference that increases financial risk without a college education somewhat is that you are a bit less flexible (at least in the short term) to switch directions within the big field of software development and its related fields.
Note that this is just looking at the likely financial income assuming you mostly follow the same path. There are other aspects in choosing a college degree aside from social (e.g. prestige) and financial aspects. For instance, there might be personal development aspects, i.e. which kind of work do you want to do, which quality standards do you want to achieve. A college education can help you to think more abstractly, give you theoretical background knowledge that can help to steer your career into a more general/abstract direction (less dealing with tooling more with algorithms and architectures) or give you the backing for highly specialized jobs where you need to know all the details and be able to prove what you implement is safe and secure (e.g. cryptography, blockchain etc.). It can also simply mean you are the go-to person for the few more complex problems in an otherwise mundane project. Or it can mean that the guy who is, is less frustrated when he needs to translate the complexities under the hood to you. You obviously can achieve all that in other ways, but a college education is exactly aimed at that, so it will be hard to beat it in terms of efficiency of reaching that.
Do what feels right for you! We don't know how the job market looks in a few years. Our answers are mostly based on the current situation. We also have no idea how you want to develop yourself, how ambitious you are etc. Maybe you become a manager in a year and then you don't need much technical knowledge anymore anyway. We can only project your financial income along a "likely path" of an average person. Much depends on a lot of other decisions you will make.
So, from my perspective: if you love what you do and you don't feel any interest in getting a college education, keep doing it. Put some money aside and consider broader education when you need it (if you hear people complaining that you just don't get the bigger picture, maybe that's a cue). If you however are curious about the bigger picture, want to learn some theory, get a broader stack etc. then you should seriously consider a college education, as that's exactly what it's meant for.