Certainly. The engines are not only larger, they burn more fuel. It is BURNT FUEL (water) that they're adding. More water added at any time is bound to beat more conditions into making trails, so the amount that appears will increase. Or maybe the trails will lengthen. maybe both.can increase the frequency of persistent contrails within the tropopause
Also the frequency of trails depends on the frequency of flights, which is still, AFAIK, increasing exponentially (although I bet that exponent has recently dwindled some).
Mick, engines that were originally 5000 lb thrust are now 80,000 lb thrust. They aren't 1600% efficient, they are burning more fuel (as well as being significantly more efficient). Whether the air comes out really hot or hotter than that makes no difference once things are down at -40. It is the water added per unit volume air, and the ambient temperature and humidity, that create trails.
I didn't mean to infer that the trails widened proportionately according to their weight. But still they will be denser than trails that start with less material. Trails can fall 22,000 feet and if they start big, and no dry layers intervene to prevent their growth, then they're bound to end up bigger still, certainly if they are shearing as they fall four and a half miles downwards. And I guess be a hundred feet wider...