Every time studies are published, we redefine the way in which could be heading towards LUCA. Maybe life on earth existed way earlier then we expected and earth recycles everything over period of time that the traces of origin are gone.
I mean, biogeochemically, we know this to be the case. The earliest evidence of life are not fossils, but changes in atmospheric chemistry recorded in the geologic record.
There are some well reasoned arguments that life is utterly common and almost inevitable when conditions are even basically adequate.
There are also lot of theories which suggest that life started at multiple places on earth and each branch could have evolved in a very different way. More like a forest rather then single point of origin.
