How so? People listing players that were selected by the Leafs in the later rounds is just as irrelevant when none has got us a Cup!
At least Detroit's late rounders have got them a Cup, and, continue to get them to the playoffs!
Teams, one team a season, gets a Cup, in the right circumstances, and it's never simply a function of saying, no Cup, no good.
Listing a player like Kaberle, who I believe saw two Conference Finals, is a way of saying, having a chance at a decent prospect is better than having an asset with diminishing or diminished value.
Using the logic that says later round picks who have led teams to Cups equates to reasonable value, is inverse thinking. If what one team, did once without intention and against likely probability was normative, you would see any number of organizations taking perfectly adequate though average assets and "covertly" trade them to other teams for their "unknown gems" of assets located in the latter rounds of a draft.
What made latter round picks like Zetterberg and Datsyuk a possibility is more than simply the potential they reached as players. It began with Jimmy Devellano and his selection of Yzerman. It then required a never again repeated draft in 89 where Detroit's scouts had the foresight to essentially draft a HOF starting lineup from Europe. Then it required moving past a decent coach in Jacques Demers to Scotty Bowman. Then it took Cups won by clubs without Zetterberg and Datsyuk by fantastically coached players in a players environment with stable, hockey-first minded ownership that provides levels of influence, example and protection for it's players.
Equating the chance provided with THAT Detroit club, to any Toronto club in the years since the 1967 club, and I'd say including ANY Toronto club, is just pure uninformed assertion.
It isn't Detroit's "late rounders" that got Detroit Cups. It's Detroit that's got their "late rounders" to the point where they could get to the Cup.
And we ain't Detroit...yet.