Really? Do you normally speak to people like that?
Despite the fact I think you are being rude and ignorant I will answer you. No, I'm not lying, I don't know anyone who just lives off teaching martial arts other than Iain Abernethy and he doesn't run schools or classes as such, he's a man of integrity and honesty who earns an honest crust.
That I don't know anyone who just earns a living from teaching martial arts in the manner you describe doesn't mean there aren't any, it means those I know, train with etc don't do it. Everyone I know, also has a 'day job'. I don't know anyone who runs schools or holds birthday parties, neither of which I disapprove of because it's none of my business what other's do, it's up to them. I imagine if you are a martial arts mad child having a birthday party in your dojo would be the height of fun for them so why not. If the owners feel they need to do this to pay the rent then good for them, I'm not going to get into the whole argument about the so called 'purity' of martial arts schools etc.
I know people who run gyms, there's kick boxing, MMA, fitness, boxercise, yoga etc etc but it's hard work and doesn't bring in as much as you'd think so many of those owners also have 'day jobs'.
There's a JKD school near me, run by a friend of my son's, it's a cracking place, lots of classes, lots of students but the owner has his own business, he doesn't make money from martial arts.
Perhaps before you start calling people liars you might like to take yourself off and give yourself a good talking to, just because you know some people who can earn a living doesn't mean the rest of us have. Just because those people earn a living from martial arts doesn't make them rip off merchants or thieves, you perhaps want to adjust your attitude and you may find a more congenial martial arts class. Rather than think you know it all, perhaps you should look at the empty cup idea. many places don't let you spar until after a certain grade, that's their prerogative, perhaps you were annoyed that they wouldn't take your word that you were this marvellous fighter who had deigned to join them and wanted to see some techniques from you before letting you loose in sparring. How dare they have such a sensible attitude!
Son, next time don't call me a liar, wind your neck in and think about what you write, twice, before you type anything up again.