Among the three Demonic Clan Limiters, Venerable Baize and Ancestor Wu Chao had both lived through long years, becoming Limiters and then waiting for the fall of a Demon God before waiting many more years. There was basically no next time for them.
However, the lifespan of the Western Sea Divine Phoenix was somewhat shorter, and it was not impossible for it to wait for the next opportunity.
As for this kind of pie-in-the-sky promise, the Divine Phoenix just took it as him farting. When a Limiter seeks enlightenment, it's all about pushing forward with no looking back. No one ever heard of taking turns like "this time it's my turn, next time it's yours."
If everything could be negotiated, might as well negotiate with the Heaven's Dao itself. How about we set up two, both Godly, wouldn't that be nice?