I've long speculated this when I see these types of comments, because it's actually really difficult to hit usage caps with an efficient dev flow, even when running multiple threads for hours every day.
I think some combination of:
1) Using 1 thread for everything
2) Reviving old threads which are no longer in cache
3) Really broad prompts on badly vibecoded codebases, so model spends huge amount of time tracking down whatever you're trying to do.
4) Non-coding workflow which is more output than input heavy
5) (Less likely IMO) Intelligent use of many passive CI/cron-like scans. E.g. regular security, quality etc scans. Automated issue resolution/PR
Just a guess. I think 3 is likely the primary reason.
You can literally go all day every day with multiple threads with Sol on the Codex 100/month plan IME
That's my experience too. I've found OpenAI really quite generous with tokens. I sometimes wonder how some people manage to run out of them really. Do they just type prompts that much faster than me or use the highest reasoning mode for everything just because they can? Idk.
I generally agree with those reasons, although using a single thread may be less of an issue than it seems because of context compacting which should happen automatically when you're near the limit.