How did non-living chemical compounds generate self-replicating, complex life forms?
Torch gave a very good summary of what seems to me to be the most probable explanation.
It seems probable that replication was powered by the massive tides that existed when the early moon was 1/16th the distance away that it is now. Tides 300ft high every three hours over lava fields can power a lot of replication (heating and cooling PCR).
It seems that there are two major classes of process at work.
One class of processes are around differential survival of variant forms in different circumstances. The vast range of micro habitats available provide huge variation in the effects of the “survival filter” on what got to survive and dominate in populations.
The other class of processes is around the effects of groups of strategies associating for mutual survival. Cooperation is unstable by itself, but when accompanied by attendant strategies that remove the advantage gained by cheating (usually some form of the retaliator class of strategies like “tit for tat”), then cooperative strategies can emerge at ever higher levels. It is possible to characterise all major advances in the complexity of living systems being the result of new levels of cooperative behaviour.
So evolution is not just about competition, though competition is an important filtering mechanism that sorts and selects amongst the variations present (at all levels). A deep view of evolution is one that shows the immense power of cooperation.
And there is certainly a sense in which we have no video recordings of exactly what went on during early evolutionary history, so everything is speculative in that sense; and it does seem to the intuitions of this individual to be comfortably within the bounds of the probable.
It is unlikely that anyone will ever know the exact mechanism of precisely what chain of circumstances led to the first living cell, and it seems to me very likely that it was a complex combination of random and probable factors.
As someone who has spent many years with a strong interest in the chemistry of life, it is a set of speculations that I find profoundly intriguing and it is speculation.