OpenRouter is the evidence that yes. Its just that the idea is dumb. What you are seeing in VCs salving their own money, buying their investment out with the money they out into more successful ventures.
Look at how the same pools of capital sit on multiple sides of the market: the router, the payment layer, and the model providers... Its all the same club
Investor ---- Economic Overlap
---------------------------------------------------------
Andreessen - OpenRouter, Stripe, OpenAI, Mistral, xAI
Sequoia - OpenRouter, Stripe, OpenAI, Anthropic, xAI
CapitalG - OpenRouter, Stripe, Google/Alphabet
MenloVentures - OpenRouter, Anthropic
NVentures - OpenRouter, OpenAI, Anthropic, Mistral
AMP PBC - OpenRouter, Anthropic
Should be easy to build a competitor in a week, pitch to some VCs then have them kingmake you to a $1B exit to another portco then!