The remaining 80% all look good on paper (or they wouldn't be there) but do things like require bathrooms to be wheelchair accessible, even if there's an accessible bathroom two doors down, at a business which would be happy to extend its use to any wheelchair-using customers. Or dictate ceiling heights so that the occasional 2 meter tall customer won't hit his head on exposed pipe.
But these regulations aren't optional "best practices", they have the same weight as ones which prevent building collapse, fire, and cancer. And the sum total is a landscape which is prohibitively hostile, in many cases, to starting a small business.
This is not a scalable solution. Now does the business have to have the same hours as your business? If not, what does the handicapped person do when they have to use the restroom and it's not available? If we want disabled people to be full members of our society, we just need to pay the costs of reasonable accommodations to their needs.
2) I did point out that each regulation, taken in isolation, looks like a good idea: you're illustrating that with your objection
3) There will always be a gap between reasonable accommodation and perfect accommodation, and what's reasonable is always subject to some debate: the effect of this is to push the reasonable further out into the realm of the unreasonable, in pursuit of the perfect
After all, no one wants to strand a wheelchair user with nowhere to pee. Certainly I don't.
But no one, wheelchair or no, can enjoy a coffeeshop which never existed because the starting costs were too high.