One of my pet peeves is higher average bowlers telling lower average bowlers that if they shouldn’t have a handicap system that gives them a chance and that they should work harder and get better if they don’t like being beat up on by higher average bowlers.

There are several things there.
 
One is why are all these higher average bowlers bowling in handicap leagues for? We have more than enough higher average bowlers to make several scratch leagues but I’m aware of only one left in town and it is struggling. There is a capped league as well I believe but to me that is the same as handicapping and could say if you don’t like a stacked team then YOU need to practice and get better.

Two is while most people could always work harder at the game and improve with practice, coaching, equipment, mental aspects, etc. most have a limit of resources (time, money, and desire) to improve.

Three is simply many people do not have the physical skills in order carry a high average. I have been a good house hack for years but I have been around top national bowlers during that time. They have hand eye coordination that I can only dream of and certain other physical attributes that no matter what I did I could not compete with them.

Lower average handicap bowlers make up the bulk of league bowling and keep the game afloat financially. They should be given a fair shake and a little respect in that most are not out there bagging to keep a low average but simply trying their best with the hand they have been dealt.

Myths 21, 22, 23
http://usbcongress.http.internapcdn.net/usbcongress/bowl/rules/pdfs/Mythbusters.pdf

If you want it to be fair for everyone you must use a base number that is above what anyone can average.

What is optimal is only an opinion.  Golf's handicap system is much more complex but they use a factor of .96 to give the better player a slight advantage.

I bowl in 2 scratch leagues, and 1 handicap

The handicap one is 100%...its much easier for

120 ave to shoot 170

170 to shoot 220 even...

I gotta shoot 270 to top these guys...

I bowl with a mostly handicap stacked team so we balance out and still win...

But my question is what is the optimal handicap?

Like 80% or 90% of what?

This is just my opinion. I would say most handicap leagues should be 90% and the cap should catch all the top averages with nobody over 5 pins above the cap.

To me handicap leagues shouldn't be big money leagues, they should be mostly social. You want to bowl for money then shoe it up scratch. And in big money leagues you shouldn't have 100 pin differences in averages, I would think everyone should be within 50 pins of average.

Everyone worries about the 120 shooting 170. There is a reason why the average 120 and they probably shoot 170 about as often as the 220 shoots 270.

My point still is that no matter what the effort put in there are a lot of bowlers who just are not going to average over 200. To simply say if they don't like getting beat every week that they need to get better is just folly.

I agree with the OP. Handicap exists in order to level the playing field. If you are a high average bowler who doesn't like giving up pins, join or offer to start a scratch league. That way you don't have to worry about giving pins away. It's sometimes difficult for the higher average guys to realize that they are in the minority. My Monday night men's league is a perfect example. There are probably 10-15 of us 220 plus, some 230 plus. On the other hand, there are a ton of guys 150-170 as well. Are we really supposed to tell those guys that it's their job to keep up with the big boys? If we did, we wouldn't have a league. If I want to bowl scratch, I can bowl pot games, look for tournaments, or grab a PBA card, problem solved. That sounds a lot more reasonable than forcing out the guys who are just there to have some fun.