You need to consider what happens if you cannot find a legal job.
You say you are on a marriage visa. Do you have 400,000 baht in a Thai bank? Do you have an passive income stream in your home country providing 40,000 baht every month? You need one or the other to get a visa extension of stay,
How much cash do you have? Enough to provide 400,000 baht a year for the rest of your life? What about a pension? will your home country provide one in 30 years time?
You have to consider the future.
My wife has a shop like you suggested your wife will do. I can tell you no way will it provide an income sufficient to support a family of 4, except at poverty level.
Another factor, Once you are in Thailand, your wife can divorce you, and the kids will not be allowed to leave the country unless your wife agrees.
You are gambling with your future.