I'd hazard that a very large fraction of people who work on open PLs and open operating systems get paid --and expect to get paid -- for the effort they put into that project; take Golang, Rust, Linux, Kotlin, Java/JVM, Scala, Haskell, OCaml, Swift and so on. These are not written by homeless people. Try telling Rob Pike that he's not going to get paid for the ten years he spent on Go, and that he would only get paid for his other contributions to Google.
Further, it is an author's prerogative (whether that author is a company or an individual) to set the terms of the pricing. As a consumer you can choose to accept it and pay the price, or come up with an alternative model (like iTunes or the App Store) that changes the market.
I resent it intensely that after putting my own money and time and effort into a project (took a full year off a job), somebody just pirates it so easily. And then attempts to claim moral high ground with weasel phrases like "knowledge wants to be free" and "class barriers".