AWS has that inefficiency baked in to their design, but I'm guessing that they do efficiently deploy their IPv4 space.
That is still a problem for sure, but I thinking of places doing things like giving a printer its own subnet just because they have no incentive to be efficient.
This includes AWS, btw. You effectively get a public IPv4 with your instance, regardless of your actual needs. It actually increases your costs to get cloud instances that don't do that.