"the law of the land" is a really shitty argument for supporting something when its questioned. its an unfair burden on small businesses. large enough ones probably get enough business it makes sense to install.
Villages in my country are losing their only stores because the stores don't get enough business to make it worth the cost. These are usually villages with a high average age. What happens to the residents? Many of the elderly don't have a car. They can't exactly go over to the next town and buy a week's worth of groceries if they can't carry these.
The store closing essentially kills off the village over time. Heavy additional costs to doing business can mean that a community just goes without any service at all. It might not be a common issue now, but if it ever does appear then it's not like you can turn the economy back on like you would flip a switch.
Also, there is no ADA compliance inspector. One of their customers would have to sue or report them. If they get reported then the remediation is to come up with a plan to address the concerns in a reasonable time. You really only get in trouble when you start willfully refusing to address issues. Again, businesses have had decades to address these. If they close and kill a town now, it’s because they didn’t do the right thing when times were good for them.