Here are the people we will not get buy-in from:
1) the politically connected (left or right)
2) the wealthy
3) the academics
4) 50%+1 of the population
5) those with strong ideological leaning (left or right)
A local TDG will start with three or four neighbors working to build a local TDG constitution. Average people. People with flaws, faults, and foibles. Different races and religions. Different perspectives. Different ages and education. Their commonality is just a recognition that current system is failing and this TDG looks like something worthy of a few hours a month.
Writing this constitution gives these neighbors practice for this new way.
When their constitution is ready, they have an election. The executive committee makes the decisions until the next election, which is a year away.
The executive committee's function is to communicate with the members, recruit and train new members, help adjacent TDGs, and look to merge with adjacent TDGs.
If 1% of the population joins this movement, it will be unstoppable social/political force. We really don't need the permission or approval from the people in the list above.
TDG mergers will great training grounds for future governance. Skills and attitudes---from both the elected and general membership--will be learned along the way.
And there will be a time when the TDG looks like a better alternative than the current system. A substantial majority will prefer the TDG to the current system. There will be a transfer process, similar to one political party beating another political in an election.
And yes, this TDG will be "far superior to what we have now." But we have to work towards it. It only needs 1%.