- Everyone knows tactics are important since decades ago.
- Being good at puzzles doesn't mean winning more games (if the other aspects of your play aren't up to par).
- Fischer didn't write that book, and the format wasn't his idea. The book also wasn't tactics, it was mostly a book of back rank mate puzzles.
- Video analysis is passive learning that's hard for most people to remember a day later. Playing moves on a board and thinking is harder... but improvement isn't easy.
- If all a person has been doing is playing, then yes, it would help to mostly study for a while. After learning new things though, you have to play to learn how to properly incorporate them into your game.
After 8 years of playing chess i have realized chess tactics are critical in a players improvement and i will explain why. Chess tactics help you cheat the game in terms of improvement, a person that has solved 100 thousand chess tactics is good as if he played 100 thousand games because chess tactics help you get to the meat without cooking, getting spoon fed. Maybe that is why Bobby Fischer released a book called Bobby teaches chess and the book was entirely a book on chess tactics. Video analysis by chess grand masters is fundamental as well. Chess books are really becoming obsolete and the reason for that its because its really time consuming reading a chess book unless you are able to just click a button and the moves automatically happen. Chess should be played 10 percent and studied 90 percent if you really want to improve. I hope this helps