Which signals to investors that there is little to no expected growth. If you aren’t attracting new customers to grow your user base, then you only have the option to milk your existing customers to increase revenue.
That may work short term, but long term it signals a death knell for the company, since as the old customers retire or the studios close down, the new crop of game developers would have been trained on or adopted a different engine so aren’t going to switch to Unity. Eventually they just run out of customers.