"They tried to adopt new rifles before WW1 and again before WW2"
The British didn't attempt to adopt a new rifle before World War II. They modified the basic Lee Enfield into the No. 4 Mark I. There wasn't money to adopt a whole new rifle, and there was virtually no political will to do so.
When it became blindingly clear that The War to End All Wars.... hadn't done so, there was no time to adopt an entirely new rifle.
"Even they realized that the Lee Enfield was not the greatest rifle in the world (I am not sure why literate and illiterate armchair historians still argue about it)..."
Because it was, by far, the best rifle of its type as a combat arm -- that was proven time and again by action, not words. In the run up to World War I, when the British were looking at adopting the P13/14 rifle and a rimless .276 cartridge, there were numerous complaints against the rifle that it was not as capable a battle rifle as the Lee Enfield.
" And you are still arguing about which rifle is best, as if the rifle won or lost the war?"
Well what the hell else do you want us to do? Roam the streets in packs?
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.