Labour did well in the election and no doubt the Conservatives under-performed. However, to flip some of the positive comments on their side.
The conservatives could be in power now until 2022 at which point JC will be turning 73 in that year.
Regardless of how Labour did they did not win the election although it has made the Conservatives strength and position weaker.
By the time of the next election we may have different leaders of the Conservatives and Labour with different polices therefore any momentum Labour obtained from this election could be lost. Maybe this is the peak for Labour.
Even with a poor leader the Conservatives still pulled in more support/got more votes than Labour did.
This is certainly a wake up call though and it will be interesting to see how it all plays out.