Here's my view of this, and it's going to be in my typical long-winded fashion, so get ready.
With respect to bowling skill, and equipment knowledge and use--and using just those two criteria--I'd say there are four types of bowler.
Bowler A is a talented bowler who works hard on his game and has a higher than usual degree of versatility. He also keeps up with the equipment end of the game and has a variety of balls with different drillings and surface preps and he keeps them up well; knowing what he needs on different lanes. This guy is hard to beat, except by another bowler of the "A" type, or occasionally by...
Bowler B. He is just as talented as Bowler A, but doesn't know or care much about equipment. He uses old tracked up stuff, probably doesn't clean it, and is sometimes seen using totally inappropriate equipment for the conditions, such as the guy in my league using a Granite Gargoyle on lanes with fried heads and mids. His talent and versatility keep him ahead of most of the rest in spite of his equipment handicap.
Bowler C is probably in the intermediate to advanced intermediate class when it comes to talent and skill. He knows what he ought to be doing with his physical game, but either through sheer lack of talent, or time to get coaching and practice he just doesn't have the game to keep up with the big boys. He compensates (partially) for this by obsessively keeping up with equipment changes and becoming knowledgeable about different types of coverstocks and where they are most likely to be effective, drillings, surface preps, ball cleaning, polishing, and surface altering agents (stuff like Neotac Control-It and other products that contain slipping agents), etc. He has a spinner and keeps track of what surface preps he uses and what surface prep he used before in case he decides he likes the way the ball was better than the way he has it now. He will have equipment that is very dull and increases in shine throughout a typical (say six or eight) ball arsenal. This bowler can't compete with Bowler A, except rarely. He can top Bowler B with some regularity, but PROBABLY not over a long format.
Bowler D is Joe Bowler. He may have glimmerings of brilliance occasionally, but it's mostly an accident. He doesn't really know what he's doing, either in his physical game or in his equipment choices. He almost never beats Bowler A or Bowler B, but occasionally beats Bowler C (much to the annoyance of Bowler C) when his game and his equipment work in sync for a change. This is the guy all you pro shop operators know who comes in and buys the latest hook monster and then gets annoyed when it doesn't seem to work.
I consider myself to fall pretty much into the category of Bowler C, with occasional percolations up to the level of Bowler B. This is why I carry more equipment than seems necessary, either for the level of skill I have or the house shot I usually bowl on. I've got a couple balls for the heavy lane conditions, but I don't see those conditions much, so those balls just stay in the car while I'm bowling most of the time. I've got a couple balls that are for very dry lane conditions. I see those conditions with some frequency, but those balls start out staying in the car, too. I go and get them when I see the need. I have four balls that go in with me when I bowl, and they are all for different versions of a "medium" condition. They are carefully chosen by type, drilling, and surface prep to give me a somewhat different "look" on mediums, and I try to find and use the one that gives me the best of that elusive element known as carry. Most of the other bowlers think they all look about the same when I throw them, but I can see the difference; and if there are any of the Bowler A types around, they can see the difference too.
This is the reason I have all these bowling balls. It is the same thing that all tradesmen do. It's called using the right tool for the job. If you can afford specialized tools and know how to use them, it helps get the job done better. It helps me handle Bowler B, at least half of the time--maybe more. Bowler A is out of my range, but I nail one occasionally. Even a blind squirrel finds a nut every now and then.
One last thought...
As an engineer, I just plain enjoy all this tinkering with bowling balls, drillings, and surfaces; and trying to use my knowledge to get my game and equipment lined up for the conditions I face. I acknowledge that honing my skills would be more effective for producing a better game of bowling, but I have time to spend a few hours here and there at the spinner. I don't have time to go to the bowling alley every day--especially since I work days and trying to find someplace to practice before the second shift is over is just about impossible even if I had the time, which I don't. I accept my limitations, but my equipment knowledge allows me to maximize my scoring.
To anyone still here and awake; thank you, thank you very much.
Elvis has left the building.
Shiv
--------------------
Listening to the monotonous staccato of rain on my desk top