Draven
Count
I think those are very different examples. There is absolutely no backup option for a Life spell. Nothing else in the game can effectively duplicate or substitute for the effect. Magic items are just Life spells in a different (stored) form. The same is not true for healing. If casters don't have some variant of Cure Wounds, there are a plethora of similar options (even ignoring magic items). Potions can (and do) exist for all Cure Wound spells. High magic can produce a healing effect. Alchemy can produce a healing elixir. Armor, while not technically healing, can substitute for healing in most situations. Defensive spells and enhancement spells can substitute to a lesser degree. Even good old first aid can substitute when all other options are played out (weakly, but it is better than dying).
The difference between the availability of Life spells and the availability of some form of healing is basically the difference between night and day. I totally get why players are justifiably paranoid about Life spells. A weekend pretty much needs have gone off the rails, over the cliff, and exploded before paranoia should kick in for healing (which admittedly, does happen sometimes).
-MS
Elixir healing is not a replacement for Cure Mortal/Critical/Serious. No fighter is going to sit around and chug 15 Elixirs so that a Scholar feels justified in their use of a Cure Mort against an Undead.
Healer's Resolve is the HM ability you speak of. It's an emergency reserve, because the pool doesn't refresh like spells do. An experienced caster isn't going to say, "I should chuck these Cure Morts out, because if worst comes to worst, I can use Resolve to fix my buddies." They're going to keep -both- resources available for healing, because they know if they tap into HR now, they might not have it tomorrow.
If you're relying on First Aid, you've already lost.