Hard disagree. So You are saying that people can't celebrate their birthdays with a meal out with friends unless they are wealthy. How mean spirited 
You obviously aren't reading the many, many, many posts where the person inviting friends out for a celebratory meal does not see this as "etiquette" (an out of date and archaic "rule" IMO), nor do they see themselves as "hosting". They are merely inviting friends to join them.
Why should the birthday person stay at home and not celebrate their birthday with a meal because they can't afford to treat 10 or 15 people to a slap up meal with drinks?
You are so out of touch.
In my 40+ years of eating out in restaurants with friends for various celebrations - birthdays, anniversaries, hen dos etc never has the person celebrating paid for everyone else. We have always paid for ourselves, and in some cases paid for the birthday person.
A house party is different. The host provides all the food and some drinks, and guests always bring bottles of wine and beer as well. The same goes for a function in a function room with a buffet.
Would you decline an invitation to a birthday meal if they weren't paying for you?