They screwed up bad. The problem is when you market yourself as the most tightly written and competitive ruleset, people expect that from you. Especially when painting and narrative get left in the cold, you lose out on the grogs and hobby nerds that helped games like 40k survive their dark times. When they left, all you have left is a small core of incredibly competitive players and a ruleset that really wasn't all that well balanced either. The pure amount of salt they generated online and in person killed a lot of fresh blood attempting to enter the game. 40k is still very unbalanced, but they show they're at least attempting to fix it and on top of that never claimed to be the best balanced anyways, so fans are more willing to forgive that. Meanwhile Privateer Press made that balance and tournaments their key selling point, so when they fuck up there's a riot.
But they probably could've survived all of that, if it wasn't for the double whammy of X-Wing becoming a far better tourney game with lower buy in and hobby time and the fact that 40k 8th edition dropped and hoovered up a lot of their casual base. Their final selling point "hey, at least we're not GW and we're established" vanished overnight.
They're the ultimate warning against catering too much to tournament players. Tournament players aren't loyal to a particular game, only to competition. If you neglect lore and hobby, then you no longer have a loyal base of fans that will stick with you through the bad times, and one fuck up will end you. Im not salty toward competitive play by the way, just noting that they want competition and you could make them play with checkers for all they care, the specific game means little to them.