Really? Because I see these things all the time. Of course, there's usually market forces keeping things that way.

In case you need examples:

I can't find a good surface subdivision modeler for Android tablets.

The desktop clients for Upwork are a bloated mess.

The Field Nation mobile client crashes twice a day for me, and both the mobile client and desktop website present a massive amount of information in a cluttered, completely disorganized fashion.

The inventory/shipping tracking systems for ecommerce are either clunky, or priced out of reach for Mom and Pop eBay sellers. I can't think of any CMSs that are particularly helpful for that vertical, either.

You could make a bunch of people happy by fixing any of those (okay, I may be the only person chafing for a good surface subdivision tool for Android). Unfortunately, you're going to have a hard time making real money from any of those niches.