Exactly. It's seems clear to me, since reading this forum over the past year or so, that there's a lot of very wealthy people on this forum. Makes sense because theres a lot of older, professional, international men on here, probably a lot of guys working in finance, consultancy etc. Good for you guys, but I think you are giving the OP an overly bleak impression, somewhat detached from typical 'reality'. The reality is that in general, salaries in Tokyo really, really suck (and a lot of people are really struggling to be fair).
My wife makes around 300k, and I make quite a bit more, but nothing crazy. We live pretty comfortably here, with a centrally located apartment, albeit small. A lot of people manage to scrape by on a lot less. A lot of shop staff will make like 200k per month or even less (and will have a tiny 70k apartment in bad location). That is definitely not comfortable though.
So if its your first job out of college, and you are looking to come to Japan to have a great cultural experience (which you will), then I also think you will be fine.
But obviously, your not going to be able to shell out for 50k/hour escorts or 200k/month Sugar Babies
Theres plenty of other ways to have fun for much less though...