In Denmark and some neighboring countries there's this concept of a school you can go to just to learn stuff later in life, as an ongoing thing. There's a whole bunch of themes (sports, history, etc), and often you can book yourself in for whatever amount of time makes sense for you.
We have those in the US; we don't have a general collective name for them, but there are both private for-profit ones with a variety of (mostly narrow) specialities, either standalone or as adjuncts to other related businesses (selling, e.g., products in the field that it teaches people to act in), plus community colleges, public libraries, public parks and rec departments, and museums tend to also have programs that serve this function, despite it not being their sole or primary function.
I have a programmer friend that took welding and car repair classes at the community college. He just wanted to learn.
If you are a parent, let your children know about these extension college courses if they are interested!
It gets more complicated in the US because of unions. In many places, you can’t become a plumber or electrician without an apprenticeship, which is controlled by the trade unions. Therefore, community colleges might offer classes on plumbing or electrical, but there’s no equivalent to a certification program, because it’s not possible to become a professional just by going to school.
This source [0] says “non-dentists cannot set up or buy dental practices as an individual or partnership but they are permitted to be shareholders of a limited company which owns the practice” and “the majority of directors of that limited company cannot be non-dentists”.
[0]: https://www.plutopartners.co.uk/post/who-can-own-a-dental-bu...
That said, this isn't what most people are talking about when they are talking about starting a business.
Socially, I’d say that it is respected and regarded as a sign of dedication to ones interests.
Where do you need a degree to open a business?
So getting these qualifications are required for reskilling.
Daycare center, hairstyling and financial advisor are others that require qualifications / lic
People aren't learning these professions at folk high school are they?
So you really need education that leads to recognised qualifications.
Reality is most people wanting to retrain are going to do it as a single person business as a plumber, hair dresser or similar.