chess is becoming a lot more concrete. kids are getting stronger faster not from book reading but from basically living glued to the computer. theory and books still matter, as its often that which refines the raw pattern recognition that got your rating to the 2000 range
they are two components to getting better. One is the brute aspect. you gotta be exposed to many tabiyas, you gotta refine your raw calculating ability , you gotta memorize your openings, know your small batch of theoretical endings etc but the other is more subtle and involves perfecting your thought process. This leads you to assess positions better , know which kind of plan is better fit for a situation, knowing how to effectively prune and order your calculations etc. This is much trickier to perfect and books often help in digesting this.
While I know many teachers who respect Silman, and some even use his books as resources, I know of very few players who became titled players as a result of studying Silman.
I do know of quite a few masters who studied Chernev, Horowitz and other American writers from that era. I know even more who studied Kotov, Watson , Dvoretsky and Nunn. Two authors titled players like to denigrate the most are Nimzo and Kotov, but at least they read these two venerable authors!
Nowadays, fewer and fewer prospective masters are reading any books.