Owen makes, what, £100k/week at least? Over 3 years that would cost us £16m. He'd be 32, and there's no doubt in my mind that his best days would be a distant memory.
I don't know what sort of wages it would take to secure Jo, but even if he matches our top playes (say £50k/week) that would cost £7.8m in wages. If we can get him for £10m, he in 3 years we could have a player approaching him prime with a resale value of perhaps two or three times what we paid for him.
If we are to continue to close the gap to the Sky 4, we MUST outmanourve them in the transfer market, because we simply cannot compete financially. This means having to buy players on their way up. It's really that simple. If we simply buy cast off players whose best days are behind them then we'll just end up like... Newcastle.