(I work at OpenAI.)
Given what's happening in the US, I suspect Musk is trying to slow down both companies and damage their funding. His goal is pretty obviously to get an advantage over Anthropic and OpenAI.
The "Plus" and higher tiers are advertised as "The latest models" but if that's not true any more then Open AI is opening themselves to investigations from organisations like: https://www.accc.gov.au/
Promising "X" for $Y to everyone and then delivering "X" only to the "chosen few" at the detriment of others opens you up to lawsuits because then your product advertisement is a lie.
For a comparison, imagine a telco selling "100 Mbps for $20/mo" and then throttling the connection for customers that aren't currently favoured by the Trump administration!
I assume for more technical folks this is not needed, as it's just a marketing term. There's no need to use such words because it's obvious, none worked for months to release a worse model/phone/laptop you name it.
Hey OpenAI model go hack the new mythos for me.
Battle bots, oppression version.