Why thinking that WH3 may be abandoned/go the way of 3K is an overreaction at best
Sure, I understand I'm yelling into the void and this is ultimately a pointless post but here it goes anyway.
The revenue from release already came in and will be enough to sustain the DLC team for a long time. You have to remember they had 150k+ concurrent players in February. That's literally twice what WH1 and WH2 pulled initially, so they don't need to turn a profit on DLCs ASAP. Roughly 2.4M copies were sold. That's a lot of money.
Sure, I can see why you'd look at the player charts and say "WH3 looks just like 3K so surely they will abandon it just like 3K" but there are important differences between WH and 3K. WH2 exceeded its initial player count several times throughout its development as DLCs dropped because the DLCs change the gameplay drastically.
With WH races being much more asymmetric, unlike CA's other titles filled with humans with slight variations, each released or updated race is a new way to experience the game. Even if you play as the same factions you played before, you can fight entirely new enemies and experience new portions of the map that were added/updated.
It will see a spike in players every time a major update is released, particularly IE, and most players who played WH2 with all DLC can be expected to play WH3 with all DLC. That's not to say that all of them will, but they have a good idea of where a minimum is for DLC purchases.
The same team that worked on DLC for 2 is now working on 3, so we can expect 3 to end up at the same quality (or better) with even more content. As mentioned earlier, more people already own the game as compared to the previous two titles at and shortly after launch.
On top of that, every current and future WH3 player that the series brings in has a chance to buy WH2, WH1, AND their DLCs in the future to gain access to all the content.
This is the most lucrative opportunity they've ever created and it'd be insane for them to throw in the towel before they even release IE and give current/future owners a reason to buy previous games. The only game models that could return higher profits are pay-to-win or, potentially, MMOs with numerous expansions throughout their lifetime. There's a huge incentive for them to continue working on this game until it becomes a must-buy with high ratings/player satisfaction, and that includes factions from the two games as well.
An interesting measure of the game's viability is its playtime stats from Steam. The median playtime across all players of WH1 is 24h, WH3 is 31h, 3K is 36h, Attila is 41h, Rome 2 is 56h, and WH2 is 67h. I would consider median playtime a great indicator of a game's success/appeal and DLC potential as it shows you how much time many users are putting into the game. It's still heavily affected by release date and total owners of the game, but at least half of the owners need to play the game for median time to go up.
So what the above means is that despite 3K having two and a half more years of time, and the DLCs it had released, it's still only ahead by an average of 5h of playtime. People have played a lot of WH3. Yeah, it's no Elden Ring, but there are very few games that are. I'm actually surprised that with the release-state of the game over half of 2.4M owners have put in over 30h.
Immediate player engagement can be important, but it is not the only indicator of how many people will play the DLCs and purchase the game in the future. I bought the game knowing that I would play it for MAYBE a hundred hours before returning to WH2 until at least IE is out, and I am sure there are plenty of others who've done the same or are taking a break from TW:WH for a while to play other games after racking up thousands of hours in WH2.
Personally, I'm trying to get all of the WH2 achievements before WH3 hits a state where it sucks me back in. I dunno if I'll win but it's an interesting race and one I might not win if that first lord pack includes a few units I'd like to see added and they keep improving unit behavior.