In this case, 343 management (since replaced) used 18-month contractors to perform the engine overhaul and build the game across the several years it was in development in order to save a buck, which in turn meant there were countless holes in engine knowledge and the engine was spaghetti code. That resulted in unfinished tools for months after launch and slow game development as a result, as well as major desync issues where you could be in an entirely different area on your screen than you were according to the server. The monetization and FOMO was also off the rails, with absurdly difficult and annoying weekly challenges that were necessary to grind the battlepass and unlock anything for free. Basic color sliders were taken away in favor of "armor coatings," and as such, to date I still cannot recreate my Halo Reach Spartan even though I have all the armor pieces necessary thanks to the Season 1 battlepass (which is the only battlepass I own, since I bought it during the honeymoon period and it doesn't contain any credits to buy the next battlepass). They did successfully commit to having battlepasses that don't expire, but only if you paid for it, otherwise it still expires and this was only mentioned for the first time like a week before Season 2.
The list kinda goes on and on, but the tl;dr is that devs and players alike both got hyper-fucked by Bonnie Ross.