This was many years ago so I don't know how it is today..
I reserved the cheapest standard transmission car for rent at the Frankfurt airport. When I got there they downgraded me to an automatic car. I held firm and said I reserved a standard car so that's what I must have. I had to wait over an hour but finally they found me a standard car, a much upgraded model too compared to the cheapest one I reserved.
The data doesn't bear that out. Look at the best selling cars in the US, not many cheap cars on that list. Now compare it to the best selling cars in Europe, almost only cheap cars.
Top 3 car in the US are Ford F-series, Chevy Silverado and Toyota RAV. Top 3 cars in Europe are Dacia Sandero, Renault Clio and VW Golf.