Though major sects also possess this type of elixir.
The cost of casually using such an elixir is indeed too great.
After all, the materials needed for elixirs are extremely expensive, and there are even some materials that cannot be bought no matter how much money you have.
It's not true that all materials are readily available; if all materials were at hand, you might waste them easily, but many of these materials are particularly hard to find.
Even if found, one wouldn't easily consume the elixir, as this kind of elixir is reserved for critical moments, not casually consumed during ordinary times.
Because such elixirs are exceptionally rare and not as easily imagined by all to be directly refined; these elixir materials are so rare that failing once or twice in the refining process would mean no new elixirs would appear.
