Joined: Mar 2014
Posts: 18,097
Likes: 6,551
From: ,location, location
Bikes: Foundry Chilkoot Ti W/Ultegra Di2, Salsa Timberjack Ti, Cinelli Mash Work RandoCross Fun Time Machine, 1x9 XT Parts Hybrid, Co-Motion Cascadia, Specialized Langster, Phil Wood Apple VeloXS Frame (w/DA 7400), R+M Supercharger2 Rohloff, Habanero Ti 26
In the end if you want something durable Tourney and similar is going to be far from it. Allegedly the new SRAM Transmission stuff can be stood on (and I have seen it though he kept one foot on the ground but I get it, it was a brand new bike). For a bike that comes with tourney replace it with something similar and save the money towards a bike that is more practical for your riding.
3X7 hasn't really been a thing in quality since the late 80s into the early 90s then it dropped off significantly and has gone way down since then. If your local shop has a $20 derailleur use that and you will be fine. We replaced one last year with a fairly low cost SunRace unit and it was a lot less plastic but pretty cheap and worked fine enough for the quality of bike.