Well, it did last time. It took a few years before it was noticeable, but...surely you've noticed the NHS getting worse? The roads falling apart? The reduction in local authority services? The local authorities going bankrupt? Increasing numbers of people unable to afford heating and food?
It takes years for differences in political parties to take hold; the whole point of term limits is that the electorate are supposed to figure out what's going on before one party can do too much damage. This time, though, everything was decided on the back of a single issue which the public were fooled into perceiving as more important than funding infrastructure and the basics (well, that and the Opposition being absolutely incompetent).
The flip side of this is that there's no silver bullet for fixing it; redressing those issues generally takes twice as long as it took to create them, and that's if you're starting with a reasonably decent set of finances. As it is, if Labour take over, they're going to find the coffers empty and borrowing ridiculously expensive as our rating gets downgraded.
I very much doubt that they'll get more than one term to sort it out, though, because the electorate has the attention span and patience of a caffeinated gnat.
Best settle in for a couple of decades of rot, folks, because it's not going to get any better than this.