Who are the Big 4 AI Labs?
To me there are the clear big 2 that actually seem to be innovating and pushing things forward. Meta almost earned a seat at the table with the open strategy then stagnated. Google obviously is the OG but at this point they seem in the same bucket as Amazon and Microsoft as "Big Enough To Matter and Influence Politics and Spend Billions To Hang Around". But they're nowhere near the same tier as OpenAI and Anthropic.
Oh and of course there's SpaceXAI which is Elon's personal money and reputation laundering corporate entity. Elon took over the "king of the reality distortion field" from Jobs as far as the rest of the industry is concerned, so he'll stay first in line for Jensen's chips and investor dollars until he's dead. But as a company what have they actually accomplished besides making the models with the sense of humour and judgement of 14 year old boys?
You can pick any 4 you like from your list. Heck you can even vote with your money on which would be in the top 4 (depending on how many align with your ideology). I am just speculating it will be 4 because of how all other sectors have at least 3 or 4 well-entrenched players. It seems to be by design. My guess is that it is driven by structure of the Military-Industrial Complex. That has at least 3 or 4 vendors in each sector, so as to not over-rely on any one company and create a monopoly in that specific industry.