Basing investment decisions on stock price leads to bad outcomes
Investment is a long term thing but the way the public corporations get leveraged means that there's little room for long term investment -- anything that's spent on development has to pay off and it has to pay off in terms of meeting or beating the RoI that you could get from, say, investing in real estate. This is what the reality of financialization means to business and the result is the gradual strangulation of the industry as it seeks to maintain profits while cutting costs (hence the fashion for outsourcing).
It never ends well. I remember a colleague talking about a local company, quite a large one, in terms that it 'breathed engineers' -- not a good place to work. Its facility is now a bank's office.