This game is such a disappointment!
Half life is on steam, As is DOTA(Although I assume you mean the mod on wc3) GTA V is also on steam. I haven't got a problem with say uplay as you can still buy the games on steam. The only other launcher I actually use is blizzard and that is purely for warcraft 3.
You mean to say you've never played any of the Half Life games? Or Diablo, Overwatch, DotA, Counterstrike, GTA V? That's a rough policy to live by.
Price sinking faster than the titanic did