JKR-- I do not mean literally bankrupt since a government of a country such as Canada can't be literally bankrupt.
However, it is possible to damage the government's finances such that future programs are no longer possible.
If we accept that immediate massive tax hikes are not possible (indeed the reductions in taxes came over many years) and running deficits not possible, I believe that the Cons intend to leave the government in such a state that major social programs will not be possible in the short term and a government runnign a long program of tax hikes may not be viable over a long term.
In other words if we reduce the fiscal capacity of the government to the point where it would take more than one term of progressive tax hikes you have made it no longer possible to enact much in the way of new programs. This is not a literal bankruptcy but it is in the sense that the government would be intentionally driven in to a place where it could no longer make decisions to enact programs.
I do not believe that we have ever had a party target the national finances with an eye on the viability of future government decision-making before but I am arguing that this is exactly what we are seeing. As outlandish as this accusation may seem it is a more simple and reasonable explanation that the chronic series of mistakes we would have to credit a bunch of people we have every reason to assume both know better and have a motive for pretending they don't.