In particular, free oxygen was practically non-existent. Metals, particularly iron, and metal complexes were dissolved in the water at high concentration. Processes that spawned the first life had to be compatible with all of that, and may well have depended on many details of it, most of which we can barely imagine. The ancestors of everything alive today survived the arrival of free oxygen a billion or two years later, with the loss of most dissolved metals, leaving no trace of the overwhelming majority that failed to adapt to that.
Conditions today, even without competition from existing life, might be wholly unsuitable for biogenesis.
It has three alternatives PNA, TNA and GNA that are somewhat variants of the RNA. (I'm not an expert, but my uninformed opinion is that GNA looks promising.)
Also PHAs that is very different and the iron-sulfur idea that is even more difficult. (I'm not an expert, but my uninformed opinion both look too weird and the transition to DNA is less clear.)
> A shadow biosphere is a hypothetical microbial biosphere of Earth that would use radically different biochemical and molecular processes from that of currently known life. Although life on Earth is relatively well studied, if a shadow biosphere exists it may still remain unnoticed, because the exploration of the microbial world targets primarily the biochemistry of the macro-organisms.
* Prions are like falling domino pieces. If you have a lot of standing domino pieces, and one of them falls, it may cause other domino pieces to fall. But they don't create more domino pieces, or standing pieces. They just pull down the pieces that are around. Also, they store no information, they just flip a bit from 0 to 1.
* RNA is like a small pile of glued magnets glued on their side. If you put some glued magnets in a box full of magnets and shake them, they will pick other magnets and create a inverse copy. If the side of the magnets is (magically) sticky, the copy may get glued permanently. After some more shaking, you have two piles of glued magnets moving around and collecting more magnets and making copies. They store information, because the initial pile may be NNSNSNS and the new piles will have the same pattern until there is an error in the copy.
I think the https://en.wikipedia.org/wiki/PAH_world_hypothesis is somewhat similar to your idea. IIUC they don't self reproduce, they just grow in a random order in a pattern. And the proposal is that it 's good to support the RNA bases for a small time to make it easy to build small chains.
[I remember to have read something like that about clay or crystals, but I can't find it now in the article in Wikipedia. Perhaps the idea was abandoned a long time ago.]