2017 GE:
So, they won every category of people who work for a living (and a few others who don't), and still fell short. Because they lost one group, who happen not to work for a living.
2019 GE (Con is 1st line, Lab is 2nd) - a catastrophic result in general:
Losses among the 1st 2 groups indeed, mirroring secular losses in every group, even students. But that's very clearly not why they lost the election.
In both cases, the Tory win is *entirely* down to retirees, with the rest of the groups coming out strong for Labour or roughly averaging to zero in 17 and 19 respectively.