"We encourage people who redistribute free software to charge as much as they wish or can. ... So if you are redistributing copies of free software, you might as well charge a substantial fee and make some money. Redistributing free software is a good and legitimate activity; if you do it, you might as well make a profit from it. ... Distributing free software is an opportunity to raise funds for development. Don't waste it!" https://www.gnu.org/philosophy/selling.html
Indeed! While reading the original post, I was reminded of the old essays where RMS made it abundantly clear that charging for delivery media was absolutely ok - and if you wanted GNU updates, you should send in the stamps necessary to send them back to you.
Maintaining a popular registry is very hard work, hard enough that commercial entities would rather pay than having to do it themselves. It is literally SaaS. It could absolutely be monetized for the common good - although the gamification worry is real, and the governance would be really difficult to defend from sharks. But there might be clever ways to fix those issues.
The one thing you cannot fix is the cross-planet level playing field that registries provide. Today, a small African company can pull from a registry more or less in the same way as large US corporations. If you put a toll booth up, the toll will soon be too high for people in various parts of the world.
