OW2 was just a cash grab cleverly marketed. They said they would never add a battle pass or sell heroes in Overwatch. In order to keep their promise they had to make a new game.
New game? But won't everyone stay on OW1? Yes. So they made the new 'game' a mandatory patch. They wouldn't get away with just patching in a store though, so they had to change things to justify it, which is where they started blind firing on random things and the promise of pve.

The game was made for 6v6, it was balanced by the end largely for 2 tanks, 2 damage and 2 support, even though the original design philosophy was to be constantly changing heroes to counter the enemies, the role lock kinda worked well (notbperfect, I think they needed to keep 1 rank and allow people to swap roles mid match) and the balance was good, well as good as it can be from blizzard.

OW2 deleted a tank spot to make it 5v5 and this completely ruined all balance the game had. They randomly changed heroes that didn't need touching, once you start fucking with core heroes that the game was balanced around, then you know its over. They removed mccrees flashbang, citing "there's too much CC in the game", but then at the same time changing orisa to have even more disgusting CC. There's so many examples of shitty changes, all made for one reason, to make each hero feel strong to the user, in order to sell skins.

The game doesn't need new heroes, it didn't need them since after Ana was released, but they wanted to sell them, so they create some strong bs and whack it in the store and in a battle pass, its new, it's strong, people are gonna wanna buy it, they cant help themselves.

They removed random systems, tried hiding others, they changed maps randomly, removed the 2CP mode only to replace it with something far worse and they destroyed the UI across the board. The game lost all its charm.

All to sell skins and battle passes. The worst thing? It was a success. People love spending $25 on skins that they only see the arms of 90% of the time.

They could have released a PVE DLC, I imagine they wanted to, but others at blizzard had other ideas. Either way, blizzard is gone, the good devs moved on or were involved in controversy. Its a skeleton crew remaining, pushing lifeless updates to the game. Overwatch is dead.