I've got a dream of one day having my own vegetarian restaurant, which I would like to call "The impenetrable fortress of death" for reasons related to mirth and the odd places from which I derive it. So I've sorta given some thought to the whole "Would it work?" question.
If there are vegetarian restaurants around, then you have competition. Now, really, the only way you can compete is with quality or price, or offer somethin gdifferent, such as all-organic or whatever.If the current vegetarian restaurant aren't doing to well for business, then you can't expect yours to do well, since there isn't much interest in vegetarian food in your area. If there are no vegetarian restaurants, then in setting on up, you'll have the market cornered, but you may not know the size of the market. It could be 2 people, it could be 2000. If you live in a city where there is a university or student population nearby, then that's usually a good sign for business. If they all vote republican in your area, it's a bad sign.
In old england, the UK vegetarian society offers cookery courses, bu tI have no idea what the prices are or anything like that. I don't know if there is anything similar in America.
And do remember: Although vegetarian food is great for everyone, the slosed-minded nature of society means that a vegetarian café or restaurant is a niché business. You don't get the same mass-market appeal as, say, mcdonalds. Also, vegetarians are amongst the more fussy members of society, so the menu will have to be well planned, which can be stressful. Many vegetarians are interested in organic food, gluten-free stuff, etc and many vegetarians are health nuts, so that makes things a lot harder. You've got a niché market which is pretty fussy, so that can be bad in a way. The main problem is that for most omnivores, the word "Vegetarian" is a huge turn-off because they have misconceptins that vegetarian food lacks taste, and is based around tofu, particularly in states such as texas. Even in England, where vegetarianism is accepted, most people will subconsciously write off a vegetarian venue in favour of a meat orientated one. I've shared my ambitions of running a vegetarian restaurant with my family, and my dad said "Personally, I wouldn't visit one, because it's gret for vegetarians, but there's nothing for me." He's basiclaly written off the idea that the place will be a good place to eat because he has mistaken vegetarian food as being bland, quite subconsciously. - This guy actually loves vegetarian food. he's amazed at how authentic my green curry was, but he still views vegetarian food as being inferior to meat, simply because meat is the norm. So there are people who wouldn't even enter a vegetarian restaurant if you dragged them in kicking and screaming. the main people wh owould go would be vegetarians and vegans, and omnivorous health nuts. Omnivorous acquaintances of vegetarians might also be customers, but they aren't likely to return on their own accord, even if the food is the best meal they've ever had, simply because returning would mean they would have to change their ideology on vegetarian food.
Despite these glitches, if there's a steady amount of vegetarians in your area, it could succeed.