I have a hard time forking over 60m for a player who isn't going to walk into the first XI, especially when that player is already entering their prime (so, it is not a youth you expect to grow into a first XI role). Granted, that's more symbolic of the modern economics of the game. We paid a fortune for Maguire and AWB, but that was to fill clear holes and for first XI roles. I'd obviously be happy with Grealish as an extra option for Pogba or Bruno's roles, and also as an outright 10 in matches, we field a 4-2-3-1. Personally though, while he probably comes with more risk as he's not EPL proven, I feel VDB makes more sense given he's likely cheaper (35m to 40m), and he seems more comfortable playing deeper while providing rotation for Pogba and Bruno, with the chance to spell Matic occasionally.
I don't know what the point in paying for a scouting staff if we can't find good rotational squad options for between 25m-40m.