nobody says it does work, their management system seems to suite a small company which valve isn't anymore. same type of problems apply to dota2 & csgo (ghost walking, tek9, smokes, hit reg, server issues, pathing, half finished features).
i agree that they should really prioritise performance, bug fixes, balancing etc. with source 2, especially as Overwatch is trying to gun for TF2 (which might be the renewed interest in matchmaking), you can't really expect such inconsistent performance on a game this old.
Matchmaking can work, however, I don't know if Valve realise how much work it's going to take to make a working 6v6 system. CSGO and Dota2 public to competitive is pretty much identically bar a few excluded heros and round timers, TF2 has a completely different ruleset, unlocks, class restrictions, maps etc. which they need to address first.