Omaster solo
Logged into today for a laugh. Saw a random Omaster raid with 3 minutes left, so thought I'd try it for a laugh. Low and behold, i won with 4 seconds left. I used this mish mash of a team. That Mewtwo was obtained in December despite me only playing once in November and not catching any Raikous.
If this sort of mish mash can win a level 3 raid, i assume level 3 raids have gotten easier since i played?

Answers
It was coldish/windy/drizzly and I obviously needed the rain bonus...also some narrative license, I was sitting in my vehicle at a Sprint store gym which neighbors a Starbucks. I already have 2 Mewtwos, if they grant me an EX pass and take it back I might get 2 preminum passes out of it. Did get a fast TM and 16 super potions. Weather changed back to cloudy 20 minutes later (been cloudy 7 straight days).
I don't understand your "complaint". PoGo doesn't set goals: players do. Just as you enjoyed the challenge of soloing a T3, others work hard to be able to duo Tyranitar. Equally, a family of casual players might get a kick out of beating a T3 together – parents and kids. There's no right or wrong way to play the game.
As long as you have one good grass attacker to get you ahead of schedule that's enough to finish the raid with a bunch of Pokemon that just about scrape 180s.
I'm not saying your team was completely optimal since the Mewtwo has a really slow time but there's worse things. None of those Pokemon are out of the ordinary for high level players to have powered. A maxed out Bellossom would be for example.