Earlier quoted context omitted.
Well, also its susceptibility to both known-plaintext attacks and statistical analysis, though it depends a bit if you're talking about the army version of the enigma or the navy version. Also until very late versions, the machine couldn't map a letter to itself, which was another critical vulnerability. The actual keyspace was around 76 bits [1], which is fairly respectable, particularly for the mid-20th century. Mu…
Another early device problem was the threat model post WWII is of course nations will put up a near Manhattan Project level of effort which turns out to be just enough to break it, everyone knows that. Pre WWII of course, they figured if a PHD mathematician couldn't crack it in a couple hours with chalk and chalkboard, well, surely they'll just give up, right? The ratio of optimism to pessimism was a bit off.
Not much has changed then.