Wasteland 2: You create up to 4 rangers, and can recruit more up to a total of 7 characters at a time. If one of them dies, they're death. You have to recruit someone else. You do have a finite number of NPCs to recruit though, and one of them is only available until the end of the halfway point for story reasons (if you take her, obviously). You can save pretty much anywhere except during fights, and can reload at any time (so is up to you to accept the failures or just try again).

Icewind Dale NON EE: You can create as many characters as you want to replace the dead ones (in case of perma-death or you simply "dismiss them"), but the Enhanced Edition removed this ability by using the BG2 engine as a base.

Icewind Dale II: A pain to get running ok (some graphics bugs actually make it LAG, specially during a Dragon fight...), but everything about IWD applies here.

Baldur's Gate/2, and IWD EE: ONLY by starting a multiplayer game, you can customize and create and replace characters as you wish. There's no "main character" as far as I know so no game over screen.

Except that the XP distribution mechanic assumes the player won't change their party mid-game. XP awarded is based on *average* party level, so adding a new low level character to the party will result in the rest of the party earning more XP than intended.

In other words, the game was not designed around the ability to add new party members later.

(Also, none of the games you mention provide an incentive to retire old characters or continue after a death.)

Are the generics useful?

I made a board game a long time ago that used this idea. You have prisoners inside of a seven level dungeon that gets increasingly large and each player represents a guild. As you gather characters, they can stay in your guild which gives your guild bonuses from outside of the dungeon and inside of the dungeon, but you also bring in one of your characters into the dungeon. The likelihood of a character dying in the dungeon is fairly high, so you end up cycling through characters in the dungeon and having to choose which bonuses you want outside of the dungeon and which character you want to fight in the dungeon. For instance a blacksmith might give you an extra plus one to your weapon if he stays out of the dungeon for the entire level, but he's also a really good fighter. So you have to weigh the option of using him to fight or keeping him at home. And then each player had the guild which gave different bonuses. For instance the wizards guild started with a collection of spells, the fighters guild started with a collection of weapons, the thieves guild gave their characters certain lock picking bonuses.

The generics can be just a good as unique recruits, although they lack personal potentials (which can be good or bad). They are mainly there to fill up your pool of recruits if you happen to lose too many of the unique ones.

Might be better off with an rpg which allows you to respec at some point midgame etc. Or at least that what is sounds like.cant think of any off the top of my head.

Honestly, mobile gacha games are probably pretty close to this, especially if you play from launch.

The inevitable power creep needed to keep driving people to the gacha means that units/characters/whatever that you start with/get from early story missions will be outclassed by units released later. It's almost certain that you'll be forced to drop a team that isn't statistically viable any more in favour of something that's just better in every way.

As for how these don't match your query-
1) The units you use in gameplay are usually entirely unconnected to the characters in the story, so even if the unit representing them became obsolete ages ago, you'll still see the same early-game characters in cutscenes.
2) The pool of units to draw from isn't infinite
3) You'll only 'lose' units by choice, removing them from your lineup because they're outclassed, not because they've been killed
4) Gacha games are predatory bull**** that deliberately sacrifice any chance they might have had of being fun or interesting in the name of constant frustrations designed to wear you down until you pay to overcome them.

How does it work in Fae Tactics, Regalia and Shadowrun? I thought thsoe games don't have permadeath, and all characters can always be revived.