You should hire young ... but not to get the best technical ability. You should hire young because we older developers, while being technically superior to our younger colleagues, don't want to put up with your bullshit. I've been on enough projects that can best be described as rearranging deck chairs on the Titanic that I don't put up with management dropping the ball. The challenge for more experienced developers…
You rearrange them to the best of ability, get some commendations on how well the chairs are arranged, and get promoted to the next sinking ship before the current one sinks.
If you're lucky you'll become an expert deck chair arranger and get lucrative consulting gigs on how a different arrangement of chairs could have saved the ship.