I'll let notclay respond with his opinion since you addressed him.
My 2 cents is that after about 100 games, there's no reason to expect that a ball will still have the same reaction it had when it was 20 or less games in age. At the end, the Ra (surface roughness in peaks) will be reduced over time and you can never get that back. Of course, you can care for a ball and that will prolong life. Prolonging life implies temporary, not forever. I have a V2 which probably has 500 or more games on it. I love it's reaction because the cover is dead. The Ra is about as low as it's going to get so there are no surprises from the ball reaction. For a new ball, the Ra will be reduced over time whether you like it or not, regardless of how much care is taken with maintenance.
As to using different mfgs vs using one, I've had periods of time where much of my arsenal may have been from one mfg, but never exclusively.
Right now, I'm keeping a Storm VG Nano, 900 Global Favorite, Ebonite Gamebreaker, Columbia Freeze, Hammer Midnight Vibe and Storm natural in my bag. I have a new HyRoad, Marvel Pearl, Critical Theory because I got into a bit of Storm preference for a while. However, they are not working for me in my current house so they stay home.
I guess if you feel comfortable understanding bowling ball cover and core characteristics (or trust your pro shop operator with that), then you can pick any ball manufacturer. Say you want a ball that covers heavier conditions and want a strong motion at the breakpoint, the Critical Theory has that ball reaction. Whereas if you prefer a smoother ball reaction at the breakpoint, you can go with the Nano. These are just examples that are a bit obvious, especially if you look at the core designs.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Everything Bowling, coaching tips, ball reviews, General bowling discussions
USBC Certified Level I