Yeah, but they reinvest very well these days
They have been, but it's hard to keep doing it and they kinda have to be perfect in order not to lose momentum as it's a crowded field between 1st and 6th right now.
I'd personally be happy for Barca or Madrid to give them even 180 million for Salah and let them spend it as ultimately if you can't keep hold of these type of players you don't usually get to move up a level. It's usually a destructive process.
I'd say he's up there with Ronaldo almost in his Man United time. While yes, Man United did cope with losing him to an extent, they've never really been as good since.