Because the time spent in seclusion was too short, just a few days of cultivation were simply not enough.
It's like this time Ye Tianfan made progress, it took him three days to progress by one-thousandth; to progress by twenty to thirty percent, he would need a much longer seclusion, at least a few years, and to progress even more, it would take several decades. To achieve earth-shattering progress, it would take dozens to hundreds of years.
