I've used many lite themes that were very nice themes and not obnoxious about upselling, though that is also less common now, unfortunately. I think it would be easier to improve the behavior of commercial themes if WordPress wasn't antagonistic to the very idea of making money. For instance, there still isn't a good notice system that allows plugins or themes to get information to users but then forbids them from harassing users excessively.

It takes financial privilege to donate lots of your time. Allowing people to make money off contributions doesn't just enable profiteering, it also enables more people to contribute.