Since the Silver Age, Beast has been defined by problems that he cannot solve.
From his scientific failures, I believe we can deduce the length of time that stories will take.
Beast failed to cure the Legacy Virus (mutant AIDS) from 1993-2001, when he eventually took credit for Mystique and Moira's cure (a cure that Kavita Rao would have come up with instead of him, if the other ladies hadn't discovered it) and, through his negligence, allowed Colossus to kill himself.
Then came the Decimation, which lasted from 2005-2013. The Scarlet Witch (an Avenger) committed genocide. There were millions and millions of mutants, and thanks to her there were only 198 left without the ability to perpetuate their species and unique mutant cultures. Make no mistake, this genocide lies entirely on the head of the witch who damned mutantdom. Beast committed himself to solving this problem. He failed.
Counting Beast's inability to transform himself back from his blue hairy ape form (1972, which he temporarily cured in 1986), we have an average of exactly 10 real-time years of failure-to-solve per insoluble scientific problem.
Q.E.D., we can deduce that the original five X-Men will be trapped in the real-time present of comics for approximately 10 years.