Comparing Egypt, Cambodia, Venezuela etc. and all other countries is irrelevant, each country has it's own uniqueness, like humans we are all different, what I have given the op is the relevant information that was asked, also what the minimum wage is compared to the U.S. Dollar, so that they have an idea of what a person's earning this money makes per day, per month.
Tips in Mexico have always been 10% to 15% that has always been the norm, I doubt very much that this will change, affluent gringos and Canadians will continue to overpay for property's, goods and services, to the detriment of the local economies, since Elisabeth Taylor and Richard Burton made the film in Mexico, very few natives can buy in the "Mexican" riviera I avoid them as if they have the plague.
I travel and stay at places where very few outsiders would go, there are no amenities, and until recently no phone, no electricity.
The information that I gathered comes from reading several articles published by the Mexican Government and my niece, she studied Hotel & Restaurant management and managed a big hotel with 2 restaurants for more than 15 years in Mexico City.
Now that we have established the minimum wage for Mexico, tip according to what you think is appropriate and makes you feel good.
Tengan un buen dia y que la conciencia no los moleste mucho.
navegator