They've already had time, and TW got more than 500k from selling the game. MP was a promised feature, it should have been finished when the game released. It should have at least been stable a couple of weeks after early access at the bare minimum.
Modders have done things in hours that still have not been implemented after years, like a basic in-game admin menu. It took them a year after early access to add invisible barriers to a couple of the skirmish maps, something a mapper can do in ten minutes if they're working slowly.
I'm convinced that the "MP dev team" is a single person who has MP issues at the bottom of his priority list. There is no other explanation.