This is a large part of what held them back: GPT3.5 had most of the capabilities of the initial ChatGPT release, just with a different interface. Yet GPT3.5 failed to get any hype because the rollout was glacial. They made some claims that it was great, but to verify this for yourself you had to wait months. Only when they finally made a product that everyone could try out at the same time, with minimal hassle, did OpenAI turn from a "niche research company" to the fastest growing start-up. And this seems to have been a one-time thing, now they are back to staggered releases.
