Hillel the Elder and Jesus were contemporaries, according to the stories.

[MineralMan]

6. Well, it probably doesn't matter, but it's important to many

to attach all those teachings to some individual, preferably an individual with direct ties to a deity. That gives them more weight. Some 2000+ years later, the actual information is lost forever. Since no eye-witnesses wrote any of what happened down at the time, we have only hearsay and a 2000 year game of Telephone to go on.

Add to that the most of the teachings that have to do with our relationships with our fellow humans are common to almost all religions and codes of laws and ethics, they have been developed independently in many places. Somehow, good advice for living is arrived at through reason, rather than revelation.

Stories of divine origins, miraculous events, conquering heroes, and the like, simply give things more weight in the minds of ordinary people. But, only if you can convince people of those divine and supernatural things, can you create a major religion.

So, no, it doesn't matter if they actually lived. It matters that people have been convinced that they did.