Redundant rebar, poverty, and Guatemala taxation

All over Guatemala (as well as Peru, Bolivia, and elsewhere), you can see buildings and houses of one level, with rebar sticking up.  I've just assumed that they hoped that one day they could build a second story on the foundation.  But a friend said that the reason they leave the rebar is because in this way, they don't owe property taxes, since it is "under construction". So they leave the rebar for years, to avoid paying taxes.  That's what I was told.

I was curious about that, and researched it to no avail (so far), but that led to some other questions and curiosities.

How does Guatemala pay for its infrastructure?  How does taxation happen here, especially personal income tax, property tax, and sales tax?

When looking up taxation and Guatemala, I found some interesting links. For instance, one website says that personal incomes up to 65,000Q ($8,300 US) are taxed between 0% and 15%, and mentions corporate taxes as well.  I am still not sure when (supposedly January? January through March?)  and how and even if the personal income tax is really collected, especially when so much of the economy here in small towns is off any books that I can tell.  Most small towns are primarily composed of very small businesses - carpenters, barbers, sellers of fruits and vegetables, corner meat markets.  Perhaps income taxes are more often collected in larger cities or hotels or chain stores with more established corporate structure.

I have wondered how the country of Guatemala (and/or, the 'departments', similar to states in the US, or municipalities) receive income to support infrastructure.  Its a very very poor country; there are a few large divided highways with good roadbeds, but most roads are rough and narrow. City streets are cobblestones with many many potholes that are never really repaired.  Where does the money come to support bridges, firehouses, police, hospitals?

Residents and Guatemalans all get a NIT (Numero de Identification Tributaria, or, Tax ID number).  We both have a NIT.  You must have a NIT to ship items to Guatemala and do some other legal or financial transactions, such as registering a car.  Also, when we make a purchase at the grocery store, we are asked if we want a factura, or invoice or receipt - and if so, we are asked for our NIT.  My understanding is that the store then has to pay some kind of taxes on that purchase, though I never see any sales tax added to our purchase.

That level of formality happens in grocery stores, furniture stores, etc, and in cities, I suppose.  But in small towns like Panajachel, there are hundreds of small businesses that are just storefronts in front of someone's house that they have converted to sell tortillas, helados (frozen fruit treats), or (in the photo below) school supplies. Just a little side income, informal, and certainly not submitting tax records to the government.

A typical neighborhood store

I will continue to research it.  I may even go into the city offices here in Panajachel just to satisfy my curiosity.  But, as I look at city services, and more broadly, at Guatemalan infrastructure, I still wonder how it even survives.  And it leads me back to the surplus rebar above many homes... just saving a few quetzales in property tax?  Stay tuned.