Yes, it is a bit surprising. Man-for-man, the Invincibles were a better team, but unfortunately for them they beat a fairly weak England team, a minnow India, and a near-minnow in South Africa in the 1940s.
The Australian team of the late 1950s beat a very highly rated England team.
Greatest Ever Test XI (according to my ratings): Hobbs, Hutton, Bradman (c), Headley, Lara, Sobers, Gilchrist (wk), Hadlee, Marshall, Steyn, Muralitharan 12th man: Imran Khan
Favorite XI: Grace (c), Trumper, Richards, Lara, Compton, Gilchrist (wk), Cairns, Jessop, Warne, Bond, Trueman