Some people who were fine with the OPTION of having their companion die wouldn't reload once they died.
Preston Garvey's quests are bland and generic and boring and each quest is the same. Stop using that as a defense.
You have the option to but you seem to have this hate-boner for mods, blah blah bethesda is lazy or some stuff. I can teach you how to install them if you need me to, if you're finding it difficult to extract zip files or something on par with your inability to understand that your opinions aren't factual in the slightest. Like I don't get it, if companions could die it would void the entire point of gaining their trust, doing their quests, ect. It may be more 'hardcore' but it's also stuff design. It worked in Fallout: New Vegas where character development was basically non-existent but in Fallout 4 the characters kinda have to be alive for more than 3 seconds for their presence in the game to even be worthwhile.
Prestons quests can be repetitive but there's nothing more satisfying than opening up your pip boy and looking over all your supply lines between different factions, building in them, watching them grow. It gives you the feeling that your faction is ACTUALLY growing. You don't have to be told it's growing by some boring richardwad in a TV screen because you're the one actually doing the building. Fallout 4 makes you the leader. New Vegas makes you a bitch to someone who's more competent. Maybe that's why you prefer it.
Cait - kill gunners.
Curie - the only one that doesn't involve killing lol.
McCready - Kill Winlock & Barnes.
Nick - kill eddie.
Boone - Kill legionnaires
Rex - Fetch an item from 1 of 3 places
Veronica - Fetch an item for Elder whoever
I can oversimplify stuff for the sake of making my argument seem more valid too. The reality is that all these quests give you great insight into the character's personal lives. In Fallout 4 many times the companion's behavior will change after these quests. Even so you're arguing about something so petty and mundane it's comical, the characters in Fallout 4 are so much better to have than some angsty dude nobody likes and some boring teenage girl who's given up on life. If I wanted to associate with either of these people I would just go watch your stream or text my ex. Fallout 4's characters have depth beyond "here's the first modicum of backstory LoL"