You found the right words. I just play for 6 years now, almost, and since then I have a meme in mind that I like as kind of Warframe-philosophie.
Sure there are other ways to protect low MR and push them a little to do the kills but thats anyway more a thing in Clan-squad-missions. I mean when I just want to quick open some relics, I rush the missions and dont care who gets the kills. Its me fine, is another faster, fine too. But yes, at the end one should wait for all to get their reactants. And with a Volt its no problem to run back real quick to buff the slower players to get to extraction, or where the reactants are, before the timer runs out.
In the end, when someone kills too fast, no one gets a drop and there is where the "single-player-power-fantasy" makes no sense for the game. Or when in an open Survival everyone runs around, splitting the enemies and the loot over the whole map instead of staying in one room.
The time before around the "lift-together"-update was really different. And to about answering questions or helping. I agree with you there but also it seems for me that players dont dare to ask, or maybe even think about it. Some days before I got an player that asks me about my Titania-build and I was happy to explain it to him. Another day I saw an player with an Hydroid, rushing through the map like nothing I have seen a Hydroid doing before. I had to ask how it worked and for a link to his build.
Jup we just can hope it will be better in Soulframe. I am really excited to play it.