1. As parallel commenters have pointed out, no. Plenty of open source developers exist who aren't interested in getting paid for their open source projects. You can tell this because some open source projects sell support or have donation links or outright sell their open source software and some do not. This line of thinking seems to come out of some utopian theoretical world where open source developers shouldn't sell their software because that makes them sell-outs but users are expected to pay them anyways.
2. I do love the idea of large companies paying for open source software they use because it tends to set up all kinds of good incentives for the long term health of software projects. That said, paying open source projects tends to be comically difficult. Large companies are optimized for negotiating enterprise software agreements with a counterparty that is primed to engage in that process. They often don't have a smooth way to like, just feed money into a Donate form, or make a really big Github or Patreon Sponsorship, etc. So even people in large companies that really want to give money to open source devs struggle to do so.
I'm not sure you realize that "open source" means anyone anywhere is free to use, modify, and redistribute the software in any way they see fit? Maybe you're thinking of freeware or shareware which often _do_ come with exceptions for commercial use?
But anyway, as an open source contributor, I have never felt I was being "stiffed" just because a company uses some software that I helped write or improve. I contribute back to projects because I find them useful and want to fix the problems that I run into so I don't have to maintain my own local patches, help others avoid the same problems, and because making the software better is how I give back to the open source community.
I don't think there's any stiffing going on, since the open source contributors knowingly contributed with a license that specifically says that payment isn't required. It is not reasonable for them to take the benefits of doing that but then expect payment anyway.