Euclidean geometry was dropped as a high school subject about 40 years ago when it was understood that most high school students will never write a proof. But of course neither can their teachers. Anyone who can construct a proof can make far more money doing something else. Instead high school geometry is nothing but nearly useless formulas and completely useless vocabulary. When was the last time you used the terms "trapezoid" or "scalene" or "supplementary angle" ? I was a graduate math student and those terms were never used after high school geometry.
"Good teachers can offer a range of speeds in their classes" Yes, they can if the class size is 15. Not if it's 30.
The difficult we do today; the impossible takes a little longer.