In these situations, it’s all too easy for staff to be distracted and fail to check regularly whether there are any customers waiting. I recall one occasion in a rural pub in Staffordshire, which had separate counters in the “dining” and “pub” sides, where I had to wait what seemed like an age before anyone noticed me, and less patient people might well have walked out.
So surely it makes sense to bring back the service bell, a staple of the old two-bar pubs, but rarely seen nowadays. At least that way you might stand a chance of actually getting served.