I don't understand the popular explanations for MMR inflation

Hi, so I've been thinking about this for a while and maybe someone can clear this up for me. please read through this before you post an explanation to avoid redundant posts.

MMR inflation, as I understand it, is when mmr increases over time for the player base without an increase in average skill. Example: a 3k player becoming 3.5k without improving.

The most common explanation I hear for this is that smurfs create mmr out of thin air. While its true this would increase total mmr, and perhaps average mmr, I don't think it would cause mmr inflation. The mmr added to the pool during the calibration of the account is given only to an account that deserves the mmr. the creation of a 4k mmr smurf doesn't distribute 4k points to the playerbase. To effect mmr inflation points have to be given to players that have not earned them. during the 10 calibration games you could argue his team has won 'unfairly' giving them +25 mmr each and causing inflation; however, the opposing team would also have lost 25 mmr unfairly. In addition their would be 5 players losing and 4 players gaining unearned mmr so their would be a net of -25 unearned mmr. Yes the smurf might gain 200 calibration mmr in the game, but presumably he deserves it.

This is similar, for those who study economics, that printing money does not cause inflation if economic growth matches the increased money supply.

The other explanations I see are that bought accounts and 0 mmr players cause mmr inflation. I agree; however do we have any evidence that these are common enough to outweigh the causes for mmr deflation? Abandons and smurfs (see above why I think smurfs actually cause slight mmr deflation) both cause slight mmr deflation and are, in my expierence, more common than o mmr games and bought accounts.

Also many people have said that players quitting dota causes mmr deflation. I don't believe this is correct. Players quitting would decrease total mmr, and potentially average mmr, but it would not take points away from players who deserve them.

So these are my thoughts on mmr inflation and deflation. Sorry for any grammatical mistakes. English is not my first language and I was in a hurry when I wrote this. Feel free to tell me where I'm wrong, I'm actually very curious to learn where my reasoning is incorrect.