According to a the following statement on page 22 of the March issue of Popular Science, electric vehicles (not necessarily motorcycles) may have a transmission in their future. Here is the statement:
Single-speed EV transmissions will give way to two-speed units within 5 to 6 years, according to German supplier ZF. As with gas powered cars, adding more gears to electric motors will make them more efficient, extending their range by up to 20 percent.
Note that ZF makes transmission for many brands of automobiles and has done so for years. I believe that they also make (or used to make) transmissions for some motorcycle brands, such as BMW.