This boils down to "having goals is important", which is certainly true, but most of us have seen managers try to improve quarterly numbers at the expense of company health. The effect is pronounced enough that people time purchases to be near other companies end of quarter, knowing they'll get a better deal.
Yep, this does happen. The point though, is to let shareholders rather than managers decide if this is a good choice. If managers are sacrificing the long-term health of the company, shareholders can vote them out or choose to sell their stake.
This is one of the downsides of the rise of passive investing and ETFs based on market cap - less votes are going into the system and holding people accountable.
uh. the fund managers vote their shares. and they've got way more time and subject matter expertise to do it than the mom & pop investors.