If Labour were comfortably ahead there would be significant push back in the party against a progressive alliance and electoral reform.
The Tories are in trouble against a progressive alliance if it happens. The longer things go, the more Brexit plays out. If the brexiters are right, these ‘teething problems’ will give way to sunlit uplands, so they ought to be hanging on as long as possible to see that.
If you are not a brexiter you really won’t be worried about these sunlit uplands coming along, politically anyway.