Money finds its way back in to the economy
This is unadulterated good news, yet people still find something to moan about. What do you think happens to the money that is paid for the shares? It finds its way back in to the economy as a whole, the founders of the businesses become millionaires, buy bigger houses, cars, invest elsewhere and in many cases of people I personally know who have benefited from an acquisition, they start up other companies using the money gained and employ more people. In many cases if you're an early employee you'll have some shares too!
I'm speaking from experience as a shareholder of a tech company that has been acquired in the last few years.