It turned up down the line that DS was a "hard-work" young child because of autism that was diagnosed later in childhood. He was 4 before I had my first smartphone with limited data and limited capacity for apps, so we did it the traditional style with toy cars, colouring etc. Generally there was a window aged 18m-3y where it just wasn't worth going out to eat unless it was part of a wider family gathering or somewhere with very quick service.
Eating at home was fine because he was called to the table when the food was ready and allowed to leave soon after. Less sensory input too.
We just had to accept what he could cope with for a few years and work at it when we did have to go out. I missed many a dessert at longer family dinners sitting in the car or walking around outside with him.
You can not expect life to be unchanged by small children and you do have to adapt and sometimes sacrifice around their needs.
When parents walk in and at the moment of sitting the tablet is whipped out with sound levels that penetrate the rest of the background throng of conversation and music it is grossly unfair on everyone else in the vincinity.
There's been times recently that it's been so bad that the moment the last person at our table has finished, that we've necked the last of our drinks and walked out (bill paid at ordering!) because selfish, lazy idiots have ruined the surrounding area for everyone else.
With younger teenagers we're stuck with "family friendly" for a few more years.
I did my graft parenting toddlers and young children and resent my enjoyment of public spaces being ruined when other parents take the lazy way out with no consideration for others.
Tablet on and I can't hear it? No problem. Might not be ideal for child development but that's not being foisted into the my problem zone. I don't have an issue with quiet tablets being used as a back-up when there are other strategies used; used with consideration, they can be a useful tool. But having it as the default option for children of normal development is not great for the child. In my youth groups, the attention spans have plummeted in the last 5 years and that's the NT children, not ND.