If modifying your shop to be accessible to everyone is not profitable for you, then you shouldn't be doing it. All this law does is require businesses to spend more money before they can operate. For now, this will hurt the economy more than it helps it.
It's not profitable. It will never be profitable. The entire point of antidiscrimination legislation like the ADA is to make things that "profit" will not cause to happen, happen, because the alternative is to exclude people based on traits they cannot change.
