I've worked multiple jobs in the service sector and I can absolutely tell you that waiters are still needed. The circumstances you are describing are essentially fast food/ small business pop and mum shops as Andrzej3K described.

However, it doesn't account for very specialized service jobs that exist in places like fine dining, luxury hotels, airlines, and other specific workplaces.

As someone who has worked in those fields you don't have any counters, and menus often don't tell you everything (for example: if the food contains something a guest is allergic to). I don't know what country you're from but in my country, we have something called RSA standards (Responsible Service of Alcohol) that is a legal requirement and must be enforced in the service sector, and last time I checked robots can't actively assess whether someone is too intoxicated to buy more drinks, you need human servers for that.

Finally, you need customer-service workers to organize and set-up the spaces that guests will be in, and cooks and bartenders can't do that because they'll always be back-of-house doing their own prep. Hell even in cheap dining places, you still need people to set-up the tables because robots aren't good enough for that.

I do however, agree that waitstaff have created a breed of guests who are incredibly entitled, self-centred, and incapable of doing work themselves, but the vast majority of them were already like that because of their class position (you think these capitalists don't treat their subordinates in their own workplaces the same?). That doesn't mean waiters shouldn't exist at all. Both can be true.