As people are paying for themselves yes it makes a big difference. Also, did you get all these guests a present on their birthday? If not you’re completely BU.
I used to have quite large birthday dinners 15-25 people and people would pay for their own dinner and sometimes chip in for mine. Some brought a present, some brought a card some neither. I really didn’t care tbh!
It can be a bit grabby if you feel entitled to people you’re not super close to bringing gifts , unless you’re talking about a close friend that you’ve always given birthday gifts to.
On my last birthday (when I turned thirty - something) I had a small gathering of a few of my closest friends - about 5 guests - which I paid for. They didn’t know I was paying until the bill came though.
Everyone had brought a present except one friend who was my oldest childhood friend and tbh I now see her as very much of a taker eg. For one of my milestone birthdays she gave me nothing, for her same milestone birthday I spent £250 on tickets for something she told me she really wanted.
It’s been a one sided friendship for our whole lives (in so many ways) but after my last birthday event I just made a mental note not to gift that friend anything again. She ended up sending me a small gift weeks later as I think she felt a bit awkward at being the only non present giver when I had paid the bill.
So yeah in some scenarios it’s poor etiquette not to bring a present but I don’t think it was in your situation.