Yes but where's the line? What if City say they're skint and can only afford £50m? By your logic, at least £50m now can buy a player, better than £150m in the bank huh?
I'm sure you wouldn't want that, so surely all we're debating is what price would be ok to let Kane go - not that we should let him go at any price. For those who rate him very highly, it's approaching £200m, for those who don't rate him that highly it's probably £100m, with most forum members presumably somewhere between £130m and £160m I'd guess...
I agree with you that we shouldn't wait and sell for £160m on the last day and have no back-up, but equally we mustn't sell cheap when everyone else does their best to get maximum value when selling, particularly for home-grown England internationals. If Levy is willing to let Kane go at all this summer, he needs to ensure replacement(s) are lined up, and tell City "pay this much by this date or he's not moving this summer".