At least, I’m classing Plantera DX as completed. I’m at the point now, at around level 155 or so, that there are diminishing returns. It takes more than a whole day’s play (or leave it for that long to generate money) to get enough cash to either expand the farm or buy the next multiplier upgrade. Doing so barely speeds up the money generation, yet the next expansion or upgrade is even more expensive.
What I’m saying, is, that upgrades are getting further away at a faster rate than money generation is speeding up.
I was going to stop when I had all the achievements, but they’re broken so I can’t. For example, one is to plant 100 trees in total. Not at the same time (the devs have specifically stated that) which is just as well as I’d have to be on level 1000 or something for that to be possible, just in total. You can bin and re-plant trees. So I did that. In one play session, I planted more than 200 trees. No achievement. I’ve planted over 400 in total, but supposedly only need 100. The same goes for bushes, plants and animals – I’ve gone way over 100, but no achievement.
I do have everything unlocked, though, so there’s that. I’m probably still going to play it a bit more too. But as far as I’m concerned, it’s done. Complete.