Cadence is a personal thing. It's best to advise people to spin, at least until they have some miles in the bank and know their own body. Some will become mashers. Others, like me, will always spin.
One of the best climbers of all time, Andy Hampsten, was a spinner because that's what worked for him.
The biggest factor, however, is, and will always be, weight. Not the bike, not technique, weight. If you take 2 similarly trained riders, the 140 lb rider will outclimb the 200 lb rider. Simple physics. Sure, there are genetic freaks out there, but it takes more watts to move more weight up a hill.
I'm over 200 pounds and I do lots of climbing rides. Did 9000 feet in 80 miles last Saturday. Done lots of 10,000 foot centuries and some over 12,000 feet. I'm slow on climbs and unless I lose some weight, I'm not going to get faster.
In order to reach the 2 pounds per inch mark I would have to lose over 50 pounds. Not possible.