The argument against live service games is that you are dependent on the servers hosted by the developer/publisher (afaik).
In normal circumstances, they are able to stop you from playing or alter the terms at any time however they like.
This is a dominant/subordinate relationship which is quite risky. Especially for young people who are still learning what a healthy relationship looks like.
The alternative is a equality relationship where you decide if you buy something based on the price.
One argument against that would be that you can „rent“ an apartment as well. But legislature has shown that states will intervene on a vendor (landlord) redefining the terms of the contract. Not so much with gaming.
Now you are arguing that the game is taken off live service and you will be able to play it offline. I don’t know if that is the case but if so then buying it now would actually send the message that doing the right thing after all boosts sales.
TL;DR: Live service games are badly legislated imo but truly making such a game offline playable with all dlc would be a good thing in my book.