The problem as I see it is that GW’s advertising and overall level of presentation is in a league of its own.
Yes, there are competing systems out there that are better.
And those aren’t as impossible to acquire as they used to be.
However they still lack the polish that GW’s output has.

And on top of that people have become used with GW’s endless production cycle which gives them new shiny things to look at every week.

Most competitors can’t match them in that, which makes the systems they produce look like they are ‘dead’ / ‘abandoned’ as they don’t have any sexy updates for months. Mantic is a perfect example. They release Deadzone, there is a short burst of activity pre and post launch as the new stuff gets mentioned … and then there is radio silence. Armada has been an exception, but only because the game was so new that not all factions were ready at release. I suspect Firefight will be similar to Deadzone.

Meanwhile GW has announced yet another expansion for Killteam, because they didn’t give the players everything in the core rules.

@wolfie65 there was a short exodus of ‘fans’ into 9th Age … but overall you are correct. The AoS release did not cause enough people to abandon GW. Quite the opposite as GW managed to make it into something that people wanted to play. It’s not quite on the same level as 40k, but it sure as heck is bigger than WFB was at that point in time.

It will be interesting to see the response to the new old world game that they’re tinkering with, although I am not expecting a game that has mechanics matching the lore … That simply isn’t what GW does. They sell minis with games attached.