if that happens then all domains would be worthless regardless of extension. not sure why you believe that would work in your favor. it is just wishful thinking.
first it is wishful thinking that companies will not buy .com for a lot of money has they have been for the last 20 years, second it is wishful thinking that if they would not do this anymore they would pay big money for .whatever.
here a few scenarios.
.com and extensions will not matter anymore = much larger supply, low prices for all domains --- .whatever investors lose
.com will not matter anymore, .whatever keywords will be popular= registries will sell great keywords, your .whatever handregs not worth much ----> .whatever investors lose
.com will remain popular = .whatever not worth much ---> .whatever investors lose.
from an investment perspective it is a horrible risk/reward ratio.
if they are successful the registries make a lot of money and you very little if any.
if they are not successful your domains are worthless.
at the moment
it looks like they are not going to be successful.
investors are betting on the dilution of .com not realising that dilution would mean that their domains would be diluted as well and not worth much anymore.