What happened in that crucial period? Did GW manage to spread its brand awareness to the mainstream public?
If I recall right that was when GW started seemingly letting pretty much every studio take a crack at making games with their IP. There was a lot of trash but the sheer number of games put out meant they kept having 1-2 a year that were popular.
Sales were down? Increase the prices of everything. Something not selling well? Change the game rules to make that it more powerful (or conversely, hype it up constantly so people only realize it sucks after they buy it). And of course constant changes so it was likely any models you bought would eventually become uncompetitive due to new, flashier, more overpowered things released.
Basically every bad business practice we see now was Games Workshop's wheelhouse. And while this may come across as bashing on them, I'm psyched to hear the company is thriving because their games are immensely fun and its impressive they've avoided stagnating or run out of ideas. It gives me hope for the software industry because if an in-person, expensive niche hobby could survive through social media and the pandemic, tech can bounce back from the current enshitification and short-term profit seeking.
If you have the money and enjoy lots of lore/worldbuilding and complex strategy games, Warhammer is a fantastic hobby I'd recommend checking out
It probably didn't sell because it wasn't very good. So you re-balance it later and now it doesn't suck. Like, fundamentally keeping the "best" and "worst" models/armies/strategies from stagnating keeps the game interesting (and drives more sales... so depends how you look at it).
I don't think they've every been super good at balancing though, and that at least is a fair criticism - albeit a hard task given how time consuming playtesting is to get data.
It didn't help they had 2 very different philosophies in the creative/design department. For example if an army was getting a revamp, competitive players would pray Gav Thorpe wasn't in charge of it. Whereas other people loved how he made the game more fun and goofy.
Again, I'm proud of the Warhammer folks. It's just the fact that it's one of the "biggest" makes me sad.