I don't know about all that. I admittedly have more experience with ChunSoft titles (Shiren is like my favorite game of all time) than I do with NetHack and Angband, but you can certainly grind in at least that branch of classic roguelikes. You have to manage your character while you do it, yes, but it's possible and a positive thing to do.
I haven't played Shiren (I actually own Shiren the Wanderer for DS, but don't own a DS).
I suppose there are always exceptions, but as a general rule you'll usually find mechanisms in place (hunger being the classic) that force you to move along, often in combination with non-regenerating monsters (forcing a limited food supply per level, and thus there's no reason/way to create unlimited experience generation.
I'm sure a couple break that rule (Shiren, as you say), but I'd still consider it a defining element of the genre.
Rogue Legacy is a Roguelike with a safety mechanism in that each time you die at least you're making a LITTLE progress
The problem with making progress of this sort in a rogue-like is that it breaks game balance in such a way that the game is
1) easy on later playthroughs due to having acquired permanent perks
and
2) a fresh character has absolutely no chance unless they die dozens or hundreds of times to 'rack up' this 'progress'.
For example, an experienced player of Nethack could take a fresh install of Nethack and do well since all games start at ground zero. But if you take a meta-progress game, such as Rogue Legacy (which I haven't played but am basing it on the discussion here), that same expert player would have, on a fresh install, a woefully underpowered character that simply hasn't 'unlocked' enough perks/whatever to get past a certain point.
The 'skill' has been removed to some degree - it's no longer the player's learned wisdom and wise choices generating survivability for the current character, but rather, past deaths that ticked up some 'progress' counter and let them start with a fire sword of doom and invisibility every game.
That's the beauty of a grindless game -- the developers can work on balancing it. A game with meta-progress can never be truly balanced, for it's got to be too difficult for starting characters, and will ultimately be too easy once you have fully leveled the meta-game. That's the cost of having the starting character so variable based on past-playthroughs.
Going rogue-like for a second, it would be like if you got to keep all the best items in Binding of Isaac... if you find, say, pyromaniac on your first playthrough you'd effectively break the game and it would be too easy forevermore.
So, basically, that illusion of 'progress' actually makes the game harder, not easier. Until you die a couple hundred times, of course, at which point the game is now too easy. Give me permadeath and no meta-game any day. (unlocks such as new starting races, etc, are perfectly fine, that still creates a sense of progress w/o affecting balance of all future playthroughs).