Cuban Mechanics and BMW's

Having heard that Cubans are industriously inventive and entirely adept at improvisation with mechanical matters, or with any matter whatsoever, one might be inclined to portion out a ration of faith and hope, which Cubans would receive not altogether ungratefully with a small mark in their state issued libreta (ration record book). Seeing that the Cubans have managed to keep the old máquinas (the classic American cars), the mechanical beasts on the streets next to the organic beasts of burden, for fifty y pico years, one can rest assured that his or her hope and faith in the ingenuity of the Cuban is well founded.
My question is where does this go wrong? A BMW was rented to carry wheelbarrows across the country. A fifteen hour odyssey that cost over 500 dollars to move five wheelbarrows, an assortment of over materials and one Claudia María Menendez, Compañera, Facilitator and project coordinator. At a certain point in the night (they drove the red-eye highway to avoid the heat of the day) they got a flat tire. Out comes the spare, and on they continue undaunted. At another certain point in the night, closer to their Guantanamo destination their spare tire ponchó. Flat. They are in the middle of nowwhere, but after some diligent and dogged pursuit they discovered a ponchero. The tire is fixed and they make it the rest of the way to Guantanamo.
There is an answer to my question. We will get to it. The clues to the answer lead back to La Habana so we must follow. The car leaves Gtmo and begins the return trip, and receives its third flat tire on the trip. I know not if they had both tires repaired and so a spare was employed or if they had to forage for another ponchero, I do however know that they did finally arrive in La Habana. There must have been a diagnosis that included other problems because word we received here in Gtmo was that he BMW was toast. At least part of that diagnosis encompassed the exhaust system, which had newly been replaced and positioned too close to the wheel, and so the heat wore down three subsequent tires in a matter of 30 hours of road time.
The Mechanics went wrong is their knowledge of the portion of the anatomy of the car. The anatomy of my question has grown then: In a country were resources are so scarce and it serves everyones best interests to avoid the waste of resources like this and other exemplary examples that mechanical improvisational aptitude exists and is successful, how could these mechanics go so wrong? I know that this knowledge could not be so complete in its coverage, that it is dangerous to generalize and assume. I merely pose the questions to provoke some thought.
In truth, flat tires wantonly ravage this country. People's lives are governed more by the whim of a flat tire than by the libreta or the lack of electoral options. Out of the three bicycles I have personally used here, all three have suffered flat tires, two were chronic slow leaks, one of which became terminal. Also our chauffeur Ol'Faithful (Don Fiel) suffered a flat tire while he was conducting us back from our seed collecting picnic at the beach. In the changing of the tires, the heavy old 1957 Chevy fell off the pneumatic jack, nearly crushing Ol'Faithful. But of course, in the end his spare tired carried us safely the rest of the way home.