I think there will be differences, probably down to design/quality of materials, but I imagine they would be very small. Yeah, old kettles were much less efficient (if nothing else, there was quite a significant bulk of metal that had to be heated up alongside the water), but who's still using one of those in daily use?
He also conveniently forgets to mention that a lot of cheap modern kettles will last just about as long as the warranty period, perhaps a little longer. So that £10 "investment" might have to pay off very quickly if it is to be replaced in a year or two.
But this is just another bullshit non-story - the real story is (as if we needed more evidence) proof of the total and utter disconnection of experience that exists between the political system and the lived experience of the vast bulk of the population.