Dear Lal and friends,
The Buddha said,according to DN 26 Sutta:
https://suttacentral.net/dn26/en/sujato
it says that the lifetime of humans is changing periodically between 100.000 and 10 years.
And (maybe said in another Sutta?) that at his time, it was around 100.
That means, he is speaking about lifetime of jati of physical body, right? The human bhava can be longer.
That would make sense, since the limiting factor in the lifetime is the composite material system, i.e. the body, and his tendency to decay. The reason why human lifetime becomes 10 years old only must be related to the changes in the physical body, which becomes more prone to decay.
Hope to hear from you.