Honestly, I think this 'billion' number is also just the ball park for companies you need to pay if you want to buy them.

OpenRouter was sold for 7.5 Billion.

Lets just accept, that these people don't evaluate a company by value but by magic market "what is a sum someone needs to pay for buying a company and what company is somehow worth it to actually buy for this type of money but more in a sense of adding this to your portfolio"