Waivers cannot always override laws that protect consumers, and these laws vary widely by locale.

For one example: Where I'm at, if you sell some things "as-is" and don't disclose all known defects, you can be held liable for those defects regardless of your "as-is" agreement.

I think the Toyota decision was also one of reputation. Do you really want to sell a bunch of cars that might have been exposed to salt water?

Nothing would ruin your brand more than having thousands of new cars breaking down.

Toyota has said "don't worry we've fixed the frames on the new ones" for ~40yr now and the Tacoma still sells. If anyone can get away with it they can. Still probably not smart to risk it though.