I'll go ahead and recommend HappyCow for anyone looking for plant-based options outside of their home community.
They have a map where people can suggest places that have vegetarian or vegan options but are mostly omnivorous, or full on vegetarian or vegan restaurants, cafes, grocery stores, food trucks, you name it. I think HappyCow the company also verifies the places people upload so it's somewhat vetted.
I find that starting with HappyCow and then cross-referencing with Google Maps or OSM gives me the best results.
I was backpacking Europe. I had just left Amsterdam and gotten to Berlin. I ordered a Heineken on impulse and the bartender looked appalled and said no.
For extremely busy restaurants / cafe's where people are already waiting long periods, they probably don't want to overcomplicate things too, and increase the risk . They'd have to keep 2 different milk frothing machines, and every time a customer got sick, risk getting sued, whilst slowing down the efficiency of orders.
Whilst it might increase the number of potential customers, in practice, it might only have negatives
In Italy, at “L'Isola della Pizza” in Rome, I asked the guy if I could get a pizza with salami, pepperoni, and sausage, and the guy was like “ah, American style!”
I'm a french vegetarian living in France after living 6 years in Scotland, France is years behind on the diet inclusion issue, I was shocked how difficult it was to find a place to eat out in Paris, way too many cafe/restaurant/etc.. gets defensive and refuse to serve you if you don't have the "historical diet" (whatever that means) of france, and a lot of them don't offer any "common alternative diet" options on the menu. And it's not better outside of Paris.
Then of course there are some great places that try to include everyone regardless of their diet, and they are increasing in numbers, but they are still the exception rather than the norm which is a shame.
If you ever goes in Paris and looking for a fully vegetarian classy restaurant, I recommand "Polichinelle", it's a bit on the expensive side (~50 euro/person), but it's high level cuisine, and for a special occasion it's really worth it.
I am not a vegan but oat milk lattes are the best lattes. They are creamy, rich with flavor that's perfectly aligned w the coffee, lower in calories & more sustainable than classic dairy.
I was on vacation in Flavigny, an incredibly beautiful small village in Burgundy. I wanted my green beans straight from the garden behind the restaurant without butter and asked to use olive oil instead. The waiter was like "Why!?". It took me five minutes to convince him, he was absolutely unsympathetic and I think I had to pay extra. :)