I would normally not be fair to compare a 2018 notebook to a 2017 model, however the fact that Apple still don't have a 2018 model MBP is precisely the point. Apple's price/performance has never been good, even when they are new. They have always used build quality, OS and aesthetics to justify the extra price. That's fine, but it only gets you so much. The undeniable fact is that right now, the price/perf of the current, newest MBPs is terrible.
Again, even when they are new, MBPs have never had powerful GPUs, but have usually been pretty good on the CPU side. We can hope that the 13 and 15 inch will get 4 and 6 core CPUs respectively this year, but they are still only catching up to the competition there.
Same as before, it is not usually fair to compare a 15" and 17" notebook, however if one is in the market for a powerful notebook with a big screen, Apple doesn't offer a 17" anymore. Instead, if we want a Mac (which we do, obviously, otherwise we wouldn't be here) we have to settle for 15". That doesn't mean comparisons can then only be made with other 15" notebooks, although if they were, Apple's would still lose badly.
And as has been said multiple times here, I (and many others here) would rather a more powerful, heavier, bigger and thicker MBP than the continued trend of thinner and lighter, with resulting power and practicality sacrifices.
People who want thin and light above all else are still best served with the MacBook. There is no need to make the MBP ever more like a MacBook, they should have different target markets, and they should be kept distinct.