I mean, can’t we? If a place wants to they can just add a wifi network with a captive portal which leads patrons to a table-to-table chat system. Or a QR code per table with a flashing light next to it so you know your table have a message even if you haven’t got your phone out.
I bet it will be cheaper and easier to maintain than installing pneumatic tubes to every table too.
>captive portal which leads patrons to a table-to-table chat system
The unreliability of captive portals across devices aside, they'll make you download some app you'll never use again, or they'll take your email and spam you later.
That is not a “we can’t do it” problem. That is a “they don’t want to do it” problem.
If you want it and you think it is cool you can have prototypes in a day max. Making it usable enough so even drunk people won’t need help using it will take longer, but it is certainly more manageable than the vacuum tubes as a hobby project.
I bet it will be cheaper and easier to maintain than installing pneumatic tubes to every table too.