This is all due to 40% marketing, 50% execution and 10% credentials (with the founders being associated with creating ChatGPT).
If anyone else came up with the same concept on a Reddit thread (they have) it no-one would care without those characteristics even if you are "first".
Rebranding, execution, marketing, ex-<big_name_company> and mostly importantly, hype is what gets the investors scrambling into throwing money at you.
More like 10% 10% 80%.