You are, I think, confusing cause and effect.
I can find much to criticise about both Blair and Brown. But the "mess" that we inherited after them was not of their making. It was mainly the US banks, aided and abetted by banks in the UK that were insufficiently regulated. Perhaps Blair and Brown should have been harder with UK banks, but you can imagine how well that would have played with Conservatives and their allies in the UK media. Had we had a Conservative govt at the time, the consequences of the 2008 crash may have been far more severe. Indeed, I believe that they would have been but we can't live history twice so we will never know for certain.
This morning, all the news is about a "leak" of Labour's draft manifesto which will, according to the Conservatives, "take Britain back to the 70s". The economic circumstances of Britain in the 1970s were created, logically, by the Government in power for the first part of the decade.
That was a Labour Government of course! Must have been. Well no, actually, from 1970 (when Heath won with a lesser share of the vote than Wilson) to 1974, the Government was Conservative and the Chancellor, Antony Barber.