Rubber derivates decompose with uv radiation, heat and ozone. I live in a seaside town in the last few years, and i can see this happening lot faster, because of much higher ozone levels and heat. Some rubber and plastics either get sticky, or harden and crack.
This is unavoidable, but just a matter of time. It doesn't make any difference if you are buying a good or bad brand. In fact, some good brands decay faster as they conform more environmental regulations - recycleable materials decay faster.
Only viable countermeasure is to store bike indoors, or at least protect it from sun, extreme heat and cold, rain, which is acidic even at the poles now.
Once it starts to decompose, rubbing it with alcohol won't solve the issue. It will just remove dissolved material, but it won't stop happening. If that happens on a structural part, it is not safe to use such parts anymore, as the integrity of the element is compromised already.
Wooden or leather grips last almost forever with some care, and good for absorbing handlebar buzz. They are either heavy or expensive, though.