If someone goes from 1900 to 1200 something isn't right. Probably sandbagging to play in lower rated tournaments. Doesn't make a whole lot of sense to me why someone would do that when there isn't money at stake or anything. If the 1900 was preparing for the World Open or something and sandbagged to 1200 OTB I could see why they would want to do that. Doesn't make sense why someone would on chess.com to me at least.
500+ pt rating spreads within a 90 days..suspicious, skeptical, leery?

Does that come naturally by reading lots of chess books / playing lots of chess games?
It comes naturally by trolling. I've tried it myself, but not to the extent of AdamovYuri. However, I'm still higher-rated than him.

Does that come naturally by reading lots of chess books / playing lots of chess games?
yes but how fast you will become a master depends on your genes. good genes - faster, bad genes - very slowly.
So why aren't you a master yet? What is stopping you from reaching it?
Again, I see no incentive to cause a player to intentionally drop from 1900 to 1200 or even from 1900 to 1500. Being able to play in lower rated tournaments so I could win more often doesn't make sense as an incentive because I have to lose so often to get from 1900 to the lower rated tournament. And the subject of the original question soon went up to the 1900 level so how strong was the alleged incentive to play in lower rated tournaments?