The dominance model came out of studies of wolves held in captivity, most influentially work published in the 1940s on a group at Basel Zoo. Unrelated adults confined together do form aggressive dominance orders. The problem is that this arrangement almost never occurs in the wild.
Field studies, particularly long-term observation on Ellesmere Island and in Yellowstone, show a different structure. A typical pack is a mated pair plus pups from one or more years, with yearlings helping raise the next litter and dispersing at maturity. The breeding pair leads because they are the parents, not because they won contests. David Mech, whose 1970 book helped spread the alpha framing, has publicly argued for years that the terminology should be dropped in favour of breeding pair and parents.
The idea survives most stubbornly in dog training, where the alpha framing was applied to a domesticated species with a different social biology. It rests on captive-wolf observations that were misread and then transplanted twice over.