First: Not all tech companies are website/apps/webservice developers. Those are the companies that you've mentioned that might be founded by "a genius guy" in a garage.
In some fields, like mechanical or chemical engineering, or maybe medic equipment, experience still counts a lot and is not outdated so easily. In these fields, a retired university professor is more likely to be a founder than a wiz kid.
Then there is the problem with scale. If there are 5 people in the company, I expect the CEO to be a hand-on person. If the technical team is comprised of 5 people but there are 20+ factory floor/sales employees, I'd expect the CTO to manage the bulk of people and bureaucracy while the CEO-founder ir still hands-on with the core activity of the business.
The thing happens when there is a stratification of teams, where at some point, the tech team needs to be managed by a tech lead, and tech leads need to be managed by a software architect. In other fields, a subsystem team has its own product owner, which respond to a systems architect which also leads an integration team, and the company's technical assets are managed by an engineering director under a VP. This is what creates a big distance from the founder and the hands-on activity.
But notice that if we pick 1:5 as the healthy manager-to-managed people ratio, then 3 layers of management would imply 125 employees, all of which are working with technical stuff. This is when I believe a CEO/founder should either assume a fully executive role or place someone else as CEO while maintaining a mixed role such as when Bill Gates became "Chief Software Architect".
In extreme examples, if a company has 5 people, I'd like the CEO to be very knowledgeable both technically and in the product inner details. If a company has a thousand employees and is publicly traded, maybe it's best if the CEO was a former CEO in a different company, even if he knows nothing about the technology (John Snow style).
Investors coming along are a whole different matter. They'll normally push back the wiz-kid for the top-spot and get some white-headed war hero to manage their precious equity.