Not just chat clients, but pretty much any stable piece of SW from a major corporation that reaches peak perfection, is forced to get worse and user hostile over time, because those VPs, execs and managers in charge of it want a promotion or need to justify their bonuses on a yearly basis, so they force needless changes to have something to present to the board every year till they jump ship or retire early with their masive stock piles.
And then the next people who take over, have something to tear down and rebuild, so they can be the ones making their careers on "fixing" that product and the cycle of shittiness repeats.
They are not products anymore that need to serve the best interest of the customers, but fiefdoms and vehicles designed to propel and fuel someone's ego and career advancements at all costs.
It's an effect of perverse incentives in corporate promotions. You'll never make a career at these companies by doing QA or saying "well, the product we have was perfect already, so I did absolutely nothing to it, added no new features, just fixed some bugs and kicked back".
