In Canada, we have similar requirements, but they apply to new construction only. Renovations must be made as accessible as possible and building officials must be reasonable in discussing what is financially feasible to make an existing building more accessible. The requirements are built into the code, so I review it as part of the plan review process and stem off a lot of problems at that stage and inspect it at the final inspection stage.
Personally, the portion of the ADA that don't sit well with me is that it applies to existing construction. I don't think that is fair. If someone is already doing work then they should be trying to make their building as accessible as possible, but you shouldn't be allowed to force someone to undertake renovations when they have made no changes to their building since the act was put into place. People who can't or find it difficult to access a building will vote with their wallets, and these businesses will either make changes or lose out on sales. Government buildings, I think we can all agree, should be made accessible to all people. But all of this is just my opinion, and since I'm not even an American it is completely worthless.
I think this is what all the arguments on this section of the forum center around. One group of people who think "It is so it has to be done" and another who think "The law isn't fair". Who is right? I think they both are.