I'd say No, you don't need more than one razor. BUT, you absolutely must have no less than one razor. So if you do like a lot of guys and nick it on the faucet, drop it in the sink, or get distracted stropping and roll the edge, then you find yourself MINUS one razor.
Pre-King Gillette a razor was often more expensive than they are today given some of the wages that were paid, but wages fluctuate. I don't think it was common for a man to buy more than one razor, but it probably wasn't uncommon for a man to have more than one razor, as grandfather's passing would mean his tools would be passed down. But you have to remember too that facial hair was common and acceptable, particularly among working men, right on up until the safety razor era. As a result it was less of a necessity for the average working Joe to have a razor.
Peace,
Jim