If I get bumped up to 4.0 next year (which I won't BTW) then my computer rating is actually 3.9, correct? The closer my opponents get to 4.40 (the number in which they will likely be bumped up to 4.5), they will be steadily better than I am.
It perfectly makes sense that the playoffs are the place where the competition is most fierce. You're playing people that are the best at being 4.0s, which means they are likely as close to 4.40 as possible.
Now, whether they are artificially tanking matches to keep their rating at 4.40, or if they got there "naturally" through practice and hard work, what difference does it make? They're still the best of what 4.0 tennis has to offer -- and that's what you should be expecting going into that match. If you yourself are not the best of what a 4.0 has to offer, then you probably won't make it that far in the playoffs.
It's the difference between really good, and really, really good. Frankly, I'd be happy to make it to the playoffs. I know I'll never get that chance.