I put Moyer in the same boat as Jim Kaat, pitchers who lasted long on the MLB level because they were left-handed, lucky, healthy, and had a little talent.
Jim Kaat may not be a Hall of Famer but to ascribe 283 wins, three 20-game seasons and 17 consecutive Gold Gloves to "luck" and "a little talent" doesn't boost your credibility as an evaluator.
Kaat he not been injured for part of the 1972 season -when he was 10-2, 2.06 in only 15 starts, less than half his normal season, he could have easily won 290 or 295 games. He was still an effective MLB pitcher at 44 years of age in his final season.
You don't win a combined 500-plus MLB games, as Moyer and Katt have, because you're left-handed and lucky. Guys like Kaat and Moyer might not have had great arms late in their careers, but they could/can really pitch.