In F/OSS, it is not unusual for software to stay below 1.0 version for a long time yet still get a lot of use. Just look at how long OpenSSL, for example, was at 0.9.something, while already being of crucial importance to a lot of internet infrastructure.
The reasons for this are varied, but the most important is probably simply that free software developers don’t feel the pressure to call a product 1.0 when they don’t believe it is ready to be called that.