Only the base is aluminum and no, they don't wear out. You're not continually screwing them up and down. At the most you're only raising or lowering the sight 4x per match and even then the change in height is insignificant to the overall length of the base. As long as you still feel the "clicks" all is good.Sorry to labour the point and I could be in error too but aren't receiver sights made of aluminium, nowadays? And would they not wear out in time, leading to repeatability problems?
We have a Master class shooter at our club who has 12 national records. He uses nothing, but those "cheap" Williams sights.Yes, it is just a game. If you don't care about winning or being the best you can be, go with the Skinner. I use them on my 45-70 and they are certainly minute-of-deer accurate. However, as it has already been pointed out, you won't see anyone who's in the winner's circle using them, or even those who placed near the top. They simply aren't precision sights. Most sights that are manually adjustable aren't very good for precision. Even the Williams lack in that regard. The problem is that the windage changes due to too much backlash on the adjustment screws and aluminum parts do wear. I tried a set back in the day when I was shooting and soon gave up on them for precision shooting. Of all the types you could try, I think the Skinner might just be about the worst. Great for hunting, not so good for precision. FWIW, a good set of precision sights for shooting will run several hundred dollars. Something like MVA front and rear could hit the six hundred dollar mark. Good luck with whatever you choose...it's a lot of fun playing the game whether you win or lose. It's just more fun when you're winning.
Check the records for Dr. Peter Krook.I've won five state titles, two regional, and one third place at the nationals in silhouette. I was also a sponsored shooter for a major powder company for four years and won several large three gun matches. I'm glad you have an expert at your club, but I'm no slouch myself. I set one record at silhouette that's never been broken and I didn't do it with a Williams sight. You'd be very hard pressed to find any national class champion get on the band wagon about Williams sights for long range precision shooting. I'd say he's a very lucky fellow indeed.