I'm guessing, based on previous situations, that this game was created on PC and ported to consoles. That said it is highly likely that the game is done and is being retrained due to a timed exclusive contract. Don't misunderstand, nothing against Popcap such contracts are common these days. What's more, any money towards keeping content free in game is fine by me. I further believe this idea based on the fact PS3/PS4 did not get a version. Given the rather negative reaction XboxOne received before launch, securing a great game near launch was probably worth the money to them.
There is one other thing I can guess about the PC release. Bug/Gliches and issues such as the Wall Nut Hill wars of 2014 will likely not be as big of an issue. Games with continually updated content suffer on consoles, not being biased just stating a fact. Due to the process for fixes and add ons to console games, it takes considerably more time (Mostly due to the console creators) to release patches. Both console Minecraft and Terraria have had similar issues where a simple glitch can render the game partially unplayable for 2 sometimes 4 weeks. (What is worse, in my experience Sony consoles update faster than Microsoft) However, PC versions do not have such restrictions and can be updated at will, making emergency updates rarely take more than 2-3 days. Mistakes happen, I'm not critisizing the developers for that, coding is actually rather hard. But, the PC will very likely find such mistakes to be less frustrating in terms of time they are present in game.