You still aren't giving enough credit to Ultra, THAT is what beat the Uboats.
Couple that with the fact that we did NOT have enough Destroyer escorts, PCs, or subchasers until 1942-43 because, and this is important, priority was given to LANDING CRAFT for the proposed cross channel invasion in 1942 and 1943....and by late 42 a lot of DDs were diverted for Torch...
You like to argue in a vacuum, PS, I like letting the air in....
First, we were ALREADY at war with Germany in the fall of 1940 in the Atlantic for all intents and purposes, so you CAN'T think of Dec 1941 as the beginning of "our" war.
Take AWAY any delusions about a cross channel invasion, put Torch away, throw in England's imminent demise, (which WOULD have got us "officially" in the war sooner, if it was ever that close)and we would have had shipyards HUMMING in 40 and 41 churning out the plywood SCs and the steel PCs, Canadian style Corvettes, and the DEs and converting ALL the mothballed 4-stackers, not just the 50 or so we gave to the Royal Navy, along with arming and converting ALL the yachts, fishing boats and small craft all along the coast....the Uboat war with more Uboats would be bloodier and costlier on BOTH sides, but WOULD have turned out the SAME way....