A core function of enterprise sales is figuring out where that opportunity cost threshold is. PE often targets industries that are currently (in their estimation) priced well below that threshold.
AVGO/Broadcom in some way acts like a big PE firm, rolling up other software companies, integrating them into their huge suite of offerings, ousting the new integrated offering's competing tools from the customers environments and selling the increment, and cutting off smaller customers not willing to subscribe to the huge suite.
Moved right in with the same old price so I didn't even have to expand the budget and they threw in training for free!
but there are plenty of other reasons as well.
starting a new venture, whether from the foundation of an existing company or doing a new one takes investment and carries risk. maybe the sales relationships the existing company had were the results of decades of investment. maybe the ownership or the employees had a specific skillset or maybe they used tooling that could be bought easily anymore. maybe they had an important and established relationship with suppliers.
maybe PE moved in because the business was viable, but not really growing and there isn't sufficient upside to motivate investors.
or the business only existed because the owner just loved that thing so much and funded it at a near-loss out of family money.
or the business was based on a huge capital investment or ownership of property in a key location that happened 20 years ago and isn't possible to replicate because of changes in the environment.
there are 1000 reasons why these things aren't spherical cows.