One thing to remember is that you're not bowling on the same conditions as 25 years ago. Today's lane conditioners are more slick than ever and we're putting more of it down.
Although there are some fine urethane balls on the market, they typically are there to fill in an arsenal rather than be the first choice (unless you bowl on some very dry lanes). No one ever complains that their ball hooks, but they do get angry when they spend good money and their ball is allergic to oil, so to speak.
Every ball needs to find adequate friction to change direction. Urethane is a much slower response than reactive resin. Is that bad? No, it's just different. Your first ball back should be something versatile as possible, then you can gradually build around it with other balls that give you an array of looks on the lane, in my opinion.