I'm not sure about the US but in the UK what you're suggesting would I think be illegal. You shouldn't make things accessible just when you're a large company, that's a really disappointing approach.
This is just another reason why the US has a healthier startup culture. There are a lot of things that take effort to do that US companies can get away with not doing until forced to by law or the market, or when the opportunity costs diminish that they do it out of the goodness of the individuals' involved hearts.
Probably. My argument for healthier would mostly be on the second-order effects of having a better economy that can generate new sources of wealth. With a step back, until momentum and inertia are all that remain of the US' current dominance in startups that grow into world-changing companies providing value to all (including disabled people who benefit from accessibility), I'm default-skeptical of tinkering with the ecosystem with a top-down legal approach, especially when the approach is something like importing laws from countries without such dominance. In a way this is just "well we've kicked ass this far even though we do [morally reprehensible thing]", which by itself isn't a great argument, but paired with noticing that social systems are complex it's enough to give me a lot of pause. Even something that seems bonehead simple like saying "no more doing [morally reprehensible thing]" can have unwanted second order effects that end up with the consequence of a state worse than the previous one that included [morally reprehensible thing]. Full analysis is required by the people most capable of seeing all the effects, one of the worst outcomes is some group kicking up a stir to get some mandate passed on good intentions without thorough analysis.
Nobody is going to sue the company they've never heard of. If they have heard of you, you're in a good position to start worrying about things like accessibility/scalability/security.
Scalability is something it seems reasonable to leave until you're more sure you actually need it. There's also no legal requirement around scaling, and you're not affecting a specific group of people.
Accessibility is a legal requirement in the UK, and while you're right it's unlikely to come back to bite you as a small company, that's also a pretty crappy attitude to take. I don't like the practice of deliberately breaking the law anyway, but deliberately breaking the law requiring equal access to people with disabilities is awful.
