Probably making up the difference in the number of customers. Veganism is still a minority, depending on sources 1-3%(highest in inda up to 9%) of the population.

So running a restaurant and focusing only on a small minority might not be that sustainable if there aren't enough people on the area or there is too high competition.

Adding in the general cost of life increases over the last few years reducing the number of potential customers as well.

And it kinda makes sense why restaurants are moving away from exclusively serving some specific group.