You also have to consider Harry Kane is the exception rather than the rule. Not many players make it to that level. That being said I'd like us to take the risk in Hojlund if we can get him at the right price.
But I feel like there are many examples of players who, from a pure numbers perspective, maybe didn't put up great numbers in a season just gone by, only to put up great numbers the season after.. again not to say Hojlund will do this or go on to have a great career at all, but I prefer to look at a players attributes and not purely numbers when figuring if a player is worth taking a chance on, and I think his attributes for his age are extremely good, and the kind we are looking for in a striker
Harry Kane
13-14 - 19 apps and 4 goals
14-15 - 51 apps 31 goals
Mohamed Salah
15-16 - 42 apps 15 goals
16-17 - 41 apps 19 goals
17-18 - 52 apps 44 goals
Thierry Henry
98-99 - 19 apps 3 goals
99-00 (before xmas) - 3 apps 0 goals
99-00 (after signing with Arsenal) - 48 apps 26 goals
Robert Lewandowski
10-11 - 43 apps 9 goals
11-12 - 47 apps 30 goals
These are just a few examples, now again this isn't to compare Hojlund to any of them or to say Hojlund will have even the fraction of the career these players are having/had, but my point is to judge based purely on numbers especially at such a young age is not a way we should be judging imo. Recent players like Haaland have skewed this perspective I feel, there isn't many players at his age past or present that are absolute world class and putting up insane numbers.
If we sign Hojlund to me something like 20 goals is a very realistic possibility, which quite frankly, is a massive improvement on what we have now if nothing else. He often plays for Atalanta has a lone striker in a formation that really keeps him isolated, with his attributes just imagine the goals we could be getting with the likes of Bruno, even if you disregarded most of his attributes and only took his ability to find space and timing of runs into the box we'd have a skillset in a forward that we currently don't have, someone who poaches in the box.