Just a guess where the 3 month idea comes in, prepared Hide glue is mostly hot water which may soak into the wood somewhat, dried hide glue and sinew will pull moisture from the air and so will take longer to dry if you are making a bow in humid weather, the combination of re-moistened wood with glue and sinew sounds like something that would take a while to reach equilibrium. Titebond and other similar glues have chemical actions going with air that speeds curing and drying.
That's just my theory on why it takes three months. I could be wrong. I was wrong once. It was the time I thought that I was wrong and then it turned out that I was right.
There is a neat technique that uses radio frequency to instantly cure Titebond glue. IT's used in the furniture industry when doing big laminations. You wave an RF wand over the piece and acbracadabra! The glue has set.
Probably doesn't qualify as primitive...