Sometimes companies never make it to adulthood, maybe due to mistakes of management, or a changing market in which it can't adapt. For example, I can think of Commodore Computers, which used to be one of the largest manufacturers of PCs. Commodore lost its market share and ultimately went bankrupt. However, somebody was buying its stock up until the end even though it went down to the penny stock range. Something about companies that are sliding downhill fascinates me, perhaps because I've actually worked for a couple of them.
Profits drop, and then the company starts losing money.
What makes things worse is the better people see the trouble and jump ship early. This leaves the mediocre performers and the ones that are too close to retirement to quit. Staff cuts occur, and if they're done through early retirement and voluntary separation, more good people race to the door. Serious pain for all involved. None of this is easy.