Just to make sure I understand your argument. Are you saying that today's open source models are on par with frontier closed models of two weeks ago? By what criteria?
https://x.com/yaroslavvb/status/2067367657272422584 https://x.com/voratiq/status/2067667800643268928 https://arena.ai/leaderboard/agent
https://news.ycombinator.com/item?id=48567759
Commenters there were saying GLM 5.2 was roughly equivalent to Opus 4.8 in coding prowess, based on personal experience of the people commenting. Opus 4.8 came out on May 28 this year (so more like 3 weeks ago), GLM 5.2 came out 2 days ago.
After a while, you do start to start to skip a couple rounds of open source models until there's a notable release. That, and the resources needed to run them are increasingly bought up by the owners of frontier models