Corbyn had less money, an openly hostile media (including the state broadcaster), the election was basically ran by about six or seven people (and staffed by tens of thousands of volunteers), the entire PLP (including the Deputy Leader) took no part in the national campaign and they started twenty points behind. I don't think a major political party has ever had all that go against it, never mind have all that go against it and got better results than it has had for years.
As for the Tories - I agree they are ruthless, and I agree they will almost certainly try and fight the next election differently, but my point was that they would lose if they called another election for October.
For a start, it would require another outbreak of Labour infighting and a collapse in the polls - which is unlikely given this result, the lack of any elections coming up for them to fall out over and the looming Parliamentary recess. Secondly, they'd have to call it in August - which would mean another five months wasted from the Brexit clock that they started ticking. Thirdly, there would have to be a blatant and non-political reason for them to call the election or it would just look like they are attempting to do what they have just failed so spectacularly to do. Finally, I am not sure that CCHQ is as competent as it used to be - that manifesto for a start, but also the rehiring of Lynton Crosby despite his failures in the Goldsmith Mayoral campaign, and if they haven't decided to get rid of May (and they need to within the next nine days) it would suggest that no-one over there knows how to fix this.
The only way I could see there being another election this year is if the various Labour and Tory "moderates", backed by the minor parties, decided to try and scupper Brexit on the basis that they probably have a majority in the Commons. We would then be in really uncharted territory and I am not sure that our politics would ever be the same afterwards.