10% to 80% seems like too wide a range for your range of “how many are on the largest instance” 10% means only 1 in ten users are on the largest instance and 9/10 are spread out on the rest, If anything that seems overly fragmented. On the other end 80% means 4/5 users are on the largest instance and 1/5 are shared between all other instances which is incredibly concentrated.
I’d sugest narrowing the range to 20% to 66%, 1 in 5 on the largest instance is still plenty dispersed to ensure that there is competition/variety and 2 in 3 users on the largest instance is already well into monopoly territory.
Not really, the politicians with a Trumpian style (Johnson and Truss) came after brexit and got there because of the polarisation caused by brexit (and had the example of Trump himself). There was definitely a lot of lying and false claims that were used by the leave campaign in order to get brexit and it shared some similarities with Trump, but it wasnt politics in the the style of being completely divorced from reality and overwhelming incompetance that defines Trump.