In the way that you put it, it doesn't sound like a cash grab. But for the folks who would like a better looking version for their collection and who already bought the game and played it, they are the ones who can't have the definitive version without paying the 60$ premium to own said game. It's kind of like when movie studios get try to get you to double dip when they release a bare-bones version soon after release, then near the holidays or maybe 6-10 months releasing a Deluxe Director's Cut with 9 hours of footage and a figurine for the same price that you payed initially.
It's just hard to swallow I think for supporters of the genre and franchise to be put into a situation where if they want the "Definitive" Edition then their gonna have to pony up and pay for it.
Now, if the publishers would offer a discount upgrade program for those that are willing to mail in their old game and case to the publisher in exchange for a next gen version at a discount price, then I would think that would be more reasonable for the Tomb Raider fan that supported the franchise in early 2013.
Also, not everyone games on Steam.
I am glad that I didn't buy Tomb Raider for PS3 because I can pick up TR PS4 and I'll know that I have the "Definitive" version in my collection until PS5 rolls out; and by then I wouldn't care about any other version that they would have because of the game being old by the PS5's graphical standards most likely.
But for the thousands of folks that bought TR PS360, they are the ones who have to pull out their wallets once again if they want a better version in their home console collection.
Which sucks...