Funny, I had to replace one about a month ago and it was about the same age. I told the battery tech that I don't drive the car much and he said that's the worst thing for a battery, but that doesn't apply to you. I suppose they've figured out a way to apply "shrinkflation" to vehicle battery life. :-))

THey don't last as long and they are almost twice as expensive!

Modern vehicles abuse their batteries. Even with out the key inserted, the computers draw power, and you can hear the air dampers open or close. The electric door openers and keyless entry also draw a constant current. I measured the leakage current in my '66 GTO at 5 microamps. Try it on a modern car!
My internet is down, once again.