“For instance, Churchill wanted to invade Europe directly from North Africa instead of coming through Normandy, which was Stalin’s preference because it gave him more opportunity to gain ground in Eastern Europe. However it’s a bit much for the author to conclude that we didn’t win the war.”
Churchill got his wish with the epic fail in Italy in 1943; the Normandy “foothold in Europe” was necessary because the “toehold” in Italy couldn’t get past Albert Kesselring’s defense (which cost a lot of allied lives). Churchill knew Britain had lost the war because they had declared war to defend Poland, and the Poles were enslaved at the end of it anyway. What did British troops die for?
The Italian campaign was a rewrite of Churchill’s original plan developed in concession to Soviet objections.
Germany was coming for Britain whether Poland fell or not, and the Soviets were waiting to swoop in when Germany fell. British troops did not save Poland; they did save Britain from the same fate.