Yea they’re rare. I mean you can get one if you put in a little effort, but you won’t normally see one in circulation. Mostly from foreign banks and okinawa. More on reddit.com

IMO folks spend too much time trying to chase the best rate, in the grand scheme of things the amount you are trying to save is miniscule compared to overall cost of the trip. I do agree with getting some yen ahead of time, it's nice to land with some yen in hand and it's one less thing you have to do after landing. More on reddit.com

I got a bunch of them on our last trip and found loading them onto my old Suica was really convenient as well. More on reddit.com

Historically, because of import/export trade i think, Japan and the US have tried to maintain that 1-100 exchange rate. It's good if Japanese goods are cheaper to an American consumer, from a Japanese perspective. Since the American economy went into slowdown in 2008/2009 the dollar has been weak the world over, and so have other curriencies (the Euro, GBP etc.) while the Yen has remained stable-ish. So although historically $1 has been 100 yen most of the time, it will never be so again until the US domestic economy sorts itself out. TL;DR No one wants dollars, the US economy is fragile. Although Japan's economy has been stagnant for a long time, it's stable. Ergo, currency is more valuable. More on reddit.com