That is a gross over-generalization. There are many places to board in Japan and the above might be true for some but certainly not all of them.
Case in point: Niseko (and to a slightly lesser extent Hokkaido in general - fittingly what the OP was inquiring about) is 95+% bilingual. While I dislike the trite lines about Niseko being more like Australia than Japan, there is some basis for those comments - specifically that it could not be easier to get around as a foreigner.
I speak Japanese and it makes fuck all of a difference in Niseko.
I would go so far as to say that aside Niseko (hirafu in particular) and Hakuba (echoland and goryu), this is exactly true.
And even then its still not watertight. The best value for money in Niseko (as i found out by pure accident) is over at annupuri. I found it by accident because i foolishly got off at niseko train station the first time i turned up there around 10pm to find an empty black wasteland of nothing. I stumbled into the sento, spieled my sob story, and had the poor woman behind the counter get out her directory, phone a few places and eventually score me some super cheap accommodation (3000pn).
There i chatted with some old japanese salts (whod been riding niseko for decades) told me that only idiots buy the hirafu pass. The best value and the one they insisted anyone with a brain rode, was the annupuri season pass with a book of moiwa tickets. Anything else was a complete waste of money.
Of course you can stay at powder lodge, (i love those dudes by the way so im not saying its awful), and get super cheap accommodation next to the lifts. And you can buy the hourly tickets and sell of what you dont use (like most people seem to do who turn up for a month or so) and not do too bad. But there are options that maybe you dont get to find out about unless you have some Japanese ability or someone who can at least help you out and score that info for you. Or less offensively, there are options you might not even think to look for without knowing what sites or what engines might contain those deals.
Niseko is well catered for. Almost all restaurants have english menus, the bus drivers are a bastion of absolute patience when 40 people are trying to get off at hirafu and almost every single one of them are holding out a note and no idea how to use the change machine (and the driver is pretty much doing it for each of them in turn). Youll get by fine. In fact id dare say youll get by better than fine though in comparison to places like shiga kogen or Zao or Myoko or Yuzawa or pretty much everywhere else with the exception of hakuba. And that makes niseko obviously a very attractive option for someone without japanese. More english, more foreign investment, more deals, more packages, cheaper all round (even if the combini is odiously expensive).
You can do it all without a lick of japanese. Id even be willing to go one step further though and say that even in the most remote place you can find somewhere to kip and somewhere to ride. You can get by almost everywhere in japan without japanese. You just wont get all the choices, options, and deals your average japanese speaking person will score is all.... but youll get by.
Ill assume the 95% comment is a bit of hyperbole though since there are still plenty of japanese accommodation all over the place where no english is spoken...
how do i know this? Because of the same trip from the annupuri tale above.
The very next day i took the (looong) bus from annupuri to hirafu. As you said, i came to hirafu thinking i would be swarmed with options... it was chinese new year though, the place was heaving but i figured id score somewhere. After i turned up at that foreign info center and they told me they only had a couple of (pricey) spots available, i figured i was screwed. I got info from them about the best backpacker places and trundled off. They were all full. Doh!
So i cast my net wider and started wandering into random backpaky looking places. Almost everywhere i checked out didnt have anyone who could speak english. I know this because i could speak only a little japanese at the time. Eventually found a mega cheap place above a yakitori place (which got turned into an art gallery in 2011), but i had plenty of conversations with staff who didnt speak a word of english. It was the norm rather than the exception to be honest.
And this wasnt 20 years ago. This was 2010. As i say, the place i ended up staying was a backpacker place for a lot of the seasonal (japanese) staff, and only a couple of those cats spoke english enough to have a stilted conversation. Cheap as hell though.
As a japanese speaker, ironically you might never see this. But when youre lost in hirafu and giving yourself only a couple of hours to find a place within budget before you have to get the train back down south (or get stuck somewhere in the middle of the ride), you might not realise just how little english alternatives there are once you go through the obvious set ups.
So yeah, ive been there. Ive underplanned. Spontaneously decided to go to niseko, assumed id have no problems, and was within about an hour of riding all the way back to shizuoka by train without spending a minute on the slopes.
Of course my situation was absurd. It was completely spontaneous. But the important thing is that i HAD to go off the beaten track and into the non australian side of hirafu in order to do all this, which means i got to see it. Fortunately i could speak just enough at the time to get by. But it was damn close to be honest. And man that would have sucked. So yeah, i dont really buy the 95% even in hirafu alone. I wouldnt even buy 30% to be honest, but then i might be guilty of over emphasising my own situation at the time. :P