It was really hard to get a Bluesky invite when I did. I spent days constantly begging people and scrolling through Twitter before I happened to be the first person to see one that got posted.
I'm 100% positive I'm personally a big part of how the decision was triggered to make invite codes easier to get. They needed to make sure I was drowned out by a flood of new users after stopping me from getting an invite code for as long as possible to already be drowned out by the flood of prior users. They couldn't let me get any advantage from being early. Similar to nostr in that way, heavily designed to strategize against me and anyone else trying to survive.
It would be cool if pubky turned into what you suggest here