If we don't change managers or sign a RW who can play up top like Bale, then yeah, we should probably bring in some physical 9 who can do a job as a target man even if it's someone theoretically below our club level like a Marcus Berg, Kalinic (though hard to see that after the WC debacle) or Llorente or Janssen from Spurs on loan or a lower-end of the table target 9 like Slimani or Solomon Rondon or even a golden oldie like Guerrero from Peru since he'd likely only have to play for an hour once every couple weeks or so when Lukaku needs a rest. Basically like when Mourinho had Demba Ba.
Ideally one of Rashford or Martial wins the job backing up Lukaku outright, but especially if Martial goes, it makes sense to have an insurance policy. We really do ask our 9s to do a specific task and it's not one for 20 year old pacy forwards. Just like Klopp might prefer Firmino as a 9 to someone theoretically better in a vacuum like Lukaku, so too might we prefer a hold up 9 of worse quality than Rashford or Martial struggling to hold up the ball draped in centerbacks or win headers.
