"Sorry I'm afraid you don't understand the point at all."

That's a bit cheeky. I understand exactly the point you are making and there was a time when I thought it was right, but now I realise that it's only a very narrow aspect of the overall question of gearing ratios.

You have chosen a low-geared method that's equivalent to "granny gear" on a mountain bike. In SOME situations that MIGHT be optimal, and for sure you can go for a long time without getting tired, but you equally don't make very rapid progress. And I agree that dragging a stone with a small team is like trying to pedal up hill in top gear -- very strenuous and tiring, but get the right team size and it becomes a lot easier. For any given situation there will be an optimum ratio that maximizes the overall throughput (smallest team that can work for the longest time without undue tiring) and I'm pretty sure that the Egyptians will have got it dead right.

To build a monument like Stonehenge, time may not have been a serious consideration, but to build the Great Pyramid in 20 years required a method that was fast and the archaeological evidence points to dragging.

Like I said before, see what slope you need for gravity to propel your stone down a wooden ramp. My experiments suggest that it will be a lot greater than 1 in 15, more like 1 in 1!