Sorry that I had to rush away earlier.
To start a business in Mexico, by a foreigner, will be a challenge of the first degree. Expat competition may not be welcome. Your first hurdle will be to apply to immigration for a visa which includes the government's permission to work at a very specific occupation and location, or as an investor with lots of cash (be prepared to lose it all). Then, the necessary licences and permits, which may, or may not be granted in your lifetime unless you are Mexican and know the 'system' locally or can keep reaching into your deep pockets to 'solve problems'. Next, is your very deep responsibility for employees, their health & welfare and their unions. The short answer is to live in Mexico for quite a while before even considering a business there. I do assume that you are fluent in Spanish if you are even having this thought. That said, there are expat owned stores which cater mostly to expats in tourist areas, etc. Some are hobby stores and a few may even make a profit.