- Rackspace was sold to private equity and restructured and made public a second time.
- LogMeIn was sold to private equity
- Kaplan is part of bigger company
- Ultimate software merged with Kronos
- Shutterfly was acquired by private equity
- Wirecard is a scam.
- Grubhub is going to be acquired by a bigger competitor
- Travelport, Expedia and Bookings are 3 very similar companies which bought all the smaller competitors.
Also note that these are internet companies and do no include myriad other software companies, including enterprise tech. So I am not sure if I agree with your concern on tech being reduced to 5-10 big companies.
Going quickly through the companies there: