Sure it would definitely be worth considering keeping Pogba IF he really wanted to stay at the club and was willing to commit to a bumper and super long new contract but all indications I have heard is that this is not the case - he wants to be a galactico, he wants to go to Real Madrid, he doesn't want to go to man Utd and I think he would certainly be willing to stay at juventus this summer even if it meant losing out on some money from United BUT he will always be eying that Madrid move, so he won't be signing any contracts which lock him down for the rest of his career and his sale value will decline year on year and he doesn't extend and as it becomes clearer that he is holding out for Real who will never pay this kind of money for him. I know he's a big loss but we're taking about £100m, this kind of offer won't come along again, and you'd be mad not to take it
Wrt Higuain, really top class number 9s are now so rare in the world that there are not even enough for every elite club to have one, therefore the alternative is what juve were doing last season and seasons before which is to have an arsenal of three very very good strikers with different skill sets and use them accordingly, not in a pecking order with a 'first choice, second choice, third choice' but in a tactical/selective rotation whereby the right man or men are used for the right game and adjustments are made mid game with substitutions if necessary. Higuain would be a perfect addition to this arsenal alongside Mandzukic and Dybala, but £75m is a lot, actually it's too much, to pay for just one member of a three man unit. If I was them I would be looking at Lukaku or Diego Costa or Milik or whatever who should be available for cheaper.
I also hope this approach to a strike force is the one Chelsea will adopt