No, there's no internet police who would stop you from doing that. However you had better point your .com to Verisign's .com or so many things won't work when connected to your DNS server. Also you will never get IANA to recognise you as the new authority for .com which means people will need to go out of their way to use your root zone instead of the de-facto-standard one published by IANA.

It's a bit like signing your website certificate with your own root certificate. The protocol itself is agnostic to who issues the root certificates, but good luck convincing distros to install yours by default, so your website will only be accessible by people who go far out of their way to install it.

It's a shame, because ICANN being under US jurisdiction is effectively an attack against the DNS.

I tried to join OpenNIC once but, like many such small groups, the ingroup dynamics are quite toxic.

The boring answer is that infrastructure costs money.

You either use taxes from everyone to pay for it or you take money from the people using the thing.

it's like Wikipedia begging for money saying they don't have enough

Maybe it's useful for ICANN to delegate management to different orgs (mostly corporations) so they don't have to control every single website on earth directly

I would actually prefer for the ICANN to have even less power and for the whole system to be even more distributed

The reason is money

The social fabric of the system would fall apart if people could trivially buy top level domains. Even the not so trivial buying that ICANN began in 2015 in order to profiteer was a serious mistake (to everyone besides ICANN).

it would be a global first come first serve namespace.

This wouldn’t really reduce the scarcity though. Right now everyone wants a “.com”, because it’s the convention. If you could buy the TLD “widget” for the same price as “widget.com”, then you would just move up one level in the domain hierarchy and have the same scarcity? If anything, the fact that there are several legitimate TLD options reduces the scarcity a tiny bit?

As an aside (I’m also annoyed by domain squatters etc), it is a fascinating market study how domains are artificially scarce the way they are when everyone can easily and cheaply buy them. I am not sure there is any reasonable solution to it.