All of the aspects of etiquette in my definition, and it's just my definition, don't apply to every situation. I was describing etiquette broadly, as I see it.
In the OP's situation, the part that I believe violates etiquette is "giving" a party without providing anything.
I wouldn't give a birthday party for myself, and provide nothing.
But that's just my take on this. We're here to discuss our varying views on etiquette, and they do vary, sometimes a lot!
But as far as I see it, the birthday girl isn't claiming to be giving a party. She'd like to see people on her birthday and is organising a get-together, not hosting a party.
I'm another who sees throwing your own birthday party as completely fine. Of course no-one has to have a party, but they're supposed to be fun, not something people have to have or not.
I went to a 40th party recently which was pay-your-own-way, but where the birthday girl had chosen a place with good food at reasonable prices, that was kid-friendly, had room for all the guests to be comfortable, and gave her time to chat with people, rather than rushing around making food at home. We were happy to go, eat out, have a fun night and celebrate with her. If we had to wait to for people to host fully, I don't think anyone would have parties around here.
Plus no-one gives gifts to adult friends for their birthdays that I've ever seen.