There is a solid counter argument here (to play devil’s advocate). This is what a right wing American would say to this:

See, we don’t have to tax the rich, they’re so generous. It’s more efficient to let them have their money and donate it directly to causes. The federal government is so bad at allocating wealth, reducing taxes so more people can be like her is the way to go.

If the person above is not wealthy themselves, the following thought to this is Well, when I’m inevitably wealthy because of how great I am, I don’t want the government taxing me so I can be like her.

Then they pat themselves on the back for being so ((in an impossible future)) generous.

It’s worth thinking about how to counter this argument.

But not a bad daydream

My head cannon is that it’s more of a positional title than a rank. The real US Navy does this all the time. You can be an O-5 (rank of Commander) and be called a Captain if you’re the CO of a ship. Similarly you can be called “Commodore” if you run a squadron of boats which is usually a rank of O-6 (Captain).

So my guess is, in the time between ANH and Hoth in ESB, Han led a land campaign and keeps the honorific. Luke is sticking to his X-wing in that time and (due to his growing Jedi-ness) is apt to be a supporting team player in an existing squadron.