Unless I'm misinterpreting you, this is very much counter to what I want.
I don't want leadership to be something that's automatically thrust upon any character, at any level of play.
There are many high-level character concepts (and players who enjoy high-level play), that simply do not want to be leaders of anything.
While one can certainly derive some fun out of taking a character who doesn't want to be a leader and putting them in a leadership position, it's not every player's idea of fun, and it shouldn't be an expectation of the system.
I don't want my only options when I reach high level to be "Leader of Men" or "Villain". Those are both interesting and viable options, but they're far from the only ones.
I want leadership to be something that any character who wants it can pursue, or even start with, at any level, if it works for the campaign.
I think that "Leader of a gang of street urchins" is an entirely viable 1st level character concept, that should have followers.
I think that "Young heir to a noble title inherits earlier than expected, and must seek vengeance" is an entirely viable first level character concept, and it's not unreasonable to allow them to have a keep, retainers, and people who owe her fealty.
Support for leadership, keeps, domains, organizations, and so on and so forth can provide wonderful tools. Tying them unnecessarily to a tier of play, or a specific class, takes the tools and strips them of some of their value.
Tools that don't have these restrictions built in can easily be restricted on a campaign-by-campaign, or character-by-character basis.