Isn't this whole valuation thing for companies like Wework a bit problematic. I assume most (all?) of the existing shareholders can't sell their shares even if

Isn't this whole valuation thing for companies like Wework a bit problematic. I assume most (all?) of the existing shareholders can't sell their shares even if they wanted when new founding rounds take place. Now we get a new investor, who might acquire a relatively small part of the company for crazy price per share. Then we state that the total value of the company is now total_number_of_shares*crazy_price_per_share. And of course even for the investor it might make sense to pay extra for the investment. If you have for example participated in previous funding rounds with lower price, it may make sense to pay overprice in the subsequent rounds, since that might make your existing share more valuable.