This isn't how this works, my $dayjob has something like this in our contracts. We are obligated upload the entirety of our source code to a 3rd party escrow service as chosen by us and approved by them which will be released to the relevant parties if we become insolvent.
Whether TRMNL is actually using an escrow, who knows, but this is a problem that can and has been solved.
This is a problem that can and has been solved, but notably isn't solved by just posting this kind of "pledge" without actually setting up the escrow infrastructure.
"Past performance is not indicative of future results"
People are unreliable. They change their behavior based on circumstance. The person who posted the pledge may well mean it right now, but then some things change and it all goes out the window.
Even worse is that companies change hands. The old owners sell or, heaven forbid, the previous owner dies. When companies change owners, all previous promises have no meaning.
Whether TRMNL is actually using an escrow, who knows, but this is a problem that can and has been solved.