This abstracts away a fundamental property of skill improvement that is true for any game, but intensively true at chess: any ELO you win during a gaming session will be lost soon by a new gaming session in which you play the game tired, or unfocused, or angry, or feeling under the weather. You still improve from one session to the next, so there is a little delta because your average ELO win is greater than you average ELO loss, but it makes the overall process extremely slow.
What I'm saying is that 100 ELO doesn't make that much of a difference in skill. You probably regularly play at +200 ELO of your actual ELO. However, maintaining a clean game hygiene and actually accumulating the ELO points to reach this level of "estate" is a whole other story.