Not necessary, many ryokans still have two people minimum per room policy. Searching for staying at ryokan (ryokan for leisure travelers at tourist places, not business type in a city) for single traveler still can be challenging in Japan.

One option is to use Japanese travel agents which have offices in the U.S. JTB and H.I.S. are Japanese travel agency with offices in the U.S. Having them help you find a ryokan accepts single travelers can be easier than doing via web, especially if you are trying to make reservation on a web with English, not Japanese. I know some people insist on doing everything via web, but even today there are situations where things may be easier if you talk to live human for help.

Also, when staying at ryokans as a single traveler who does not speak Japanese. I do not know how familiar you are in Japan, but meals served at ryokan will likely nothing like what you saw at Japanese restaurants in the U.S. Japanese food is not sushi and tempura only, and there will be nobody at ryokan who can explain to you food being served.