Agreed, the Ediacaran period was a frontrunner for MCL. Shame we know so little about the transition from that period

It's completely possible that abiogenesis (or Panspermia) did occur many times, but whatever organisms emerged as a result became extinct early on or are not preserved in the fossil record.

The places on earth right now (that we know about) where sterile but minimal materials for self replication machinery are available are very rare, and only on very specific parts of the Earth. Given that, whatever primordial soup pocket that does pop up now has to compete with any loose complex organic matter around it, so good luck to my little progenitors....