It happens to all applications like that.

Remember CUSeeMe, ICQ, AOL Instant Messenger, Paltalk, ...

They start out pretty good then they rot. Something new comes along and then the cycle repeats. Right now people perceive Zoom works but 5 years from now we will be asking "How can Zoom be so bad?" and something new will come along.

It happens because instead of having multiple applications that can interoperate with each other where competition would lead to better applications, competition is based on two-sided markets that compete based on inertia.

It's lasted better in the non workplace world than Cisco webex.

Offering direct out dial to the PSTN probably did it huge favours: "it's the phone, stupid" for the generations old enough to remember and want phones.

"Works well enough" can survive a long time once on a device.

Its NAT busting was best of breed.

Much though it irks me, I continue to use it.

FTFY: "... continue to be so bad?"

See, exempli gratia, circa 2017: https://news.ycombinator.com/item?id=14691203