If you learn to throw a curve with a basic plastic ball, you've actually learned to hook the ball. If you can hook plastic you can hook anything.
Bowling balls are tools.
The more expensive the ball, the more it can do (the more it will do whether you want it to or not). When you learn with a performance ball, you learn what the ball can do, not what you can do to a ball.
Learn what you can get a ball to do, and you will NOT be a straight ball bowler anymore.
Have the store/ball driller look at how you roll a houseball, get an idea of what you do by observing your delivery and ball track on the ball. That should help the driller get an idea of what your general game is about.
As a pro shop operator and ball driller, my job is to make bowlers better. Since the bowling ball technology explosion, I've noticed many a bowler wanting to knock down more pins but with out the objective to be better, just better equipped. Better equipment is a very short term, quick fix.
Lanes change, other bowlers get in the way, etc. what to do next?
The frustration from being unable to control the lane either translates to a bowler becoming a ball-a-holic, buying new balls at every opportunity (something some stores LOVE), or just feeling so incapable that even though you've invested in top flight equipment, you've not improved your physical skills, so you don't improve significantly as a bowler, and you quit.
One of the reasons I do this, is to help others enjoy a sport I love, but a sport that demands more than just the latest ball. Tiger Woods didn't become a superstar because he got old enough to buy really expensive clubs!
Unfortunately, to use another golf analogy, bowling centers are putting out lane conditions that are way easier then they used to be, much like a green tapered into the hole like a giant funnel (we'd have a great short game then). Some centers put out lane conditions that funnel bowling balls to the pocket (head pin).
So, what I've seen lately, is the right ball, directed to the pocket by easy lanes, translates into (some) good games. But the wrong ball (maybe even the same ball), on different lanes (a ball hooking a little too much or not quite enough), a bad night and someone with a decent average looks like a beginner.
If you can't figure out what to do other than change balls, your not a bowler, just someone who bowls.
The membership organization of bowling (in the USA), the United States Bowling Congress (USBC) is pressing forward encouraging bowling centers to make available coaches to its bowlers. Even the bowling proprietors organization (Bowling Proprietors Association of America, BPAA), is encouraging a concept being called The Skills Center to encourage players to upgrade their skills not just equipment.