Have multi-speed non-freewheeling bikes ever been common?
I read somewhere about a three-speed  internal fixed rear hub, the Sturmey-Archer ASC (hmm, here maybe?; now replaced by the Sturmey-Archer S3X), and people were complaining that it had poor reliability. Obviously if something is not used in a big cycling sport (and has access to its R&amp;D budgets), it has little chances for a wider market effort.