While it’s possible, generally innovation in product ends post-acquisition.
Look at poor Yammer’s homepage. It’s stuck in 2012:
The problem, usually, is the post-acquisition product & engineering teams move into Incremental Improvement Mode when the products they buy are mature. Lots of code still gets pushed out, don’t get me wrong. It’s just incremental change to whatever the product did at the date of acquisition. Sometimes that’s enough (e.g., Skype). But if the market is very dynamic. Sometimes it’s not.