Feels like an unanswerable question, but: could we ever see something like this in mammals? A virgin birth, for lack of a better phrase?
Interestingly, there are a handful of cases of functioning human individuals who have cell lines in their body that are the result of parthenogenesis: an egg cell starts dividing by itself, and is fertilized only after this process has started. Next, the feritilized cell line develops normally, while the unfertilized cell line keeps developing as well but in limited ways - in the first known case, the white blood cells of a boy were found to be entirely derived from his mother, while other cell lines were normal XY cells inherited from both parents.
Caution when clicking, the article also contains some photos of the teratoma, which are slightly disturbing!
https://meridian.allenpress.com/aplm/article/130/10/1552/459...
The question is easy to answer. Yes, this is a development that shows up from time to time. Species displaying only asexual reproduction all tend to be evolutionarily young, which implies that adopting the strategy rapidly leads to extinction, but it has short-term benefits which mean that there's usually something around trying it out. (And then there are species with obligatory parthenogenesis and also obligatory sexual reproduction, like aphids, which don't experience the problems that pure-cloning species do.)
By way of examples of sexually-reproducing species shifting to parthenogenesis, there is a species of lizard that can only reproduce that way. We can be certain they originally reproduced sexually since they still engage in a (pointless) simulation of copulation.
"ever" is pretty open-ended. In principle, it's possible.
The most obvious problem is that if the maternal genes include any that are homozygous lethal or homozygous impaired, the embryo is also a no-go. This is in principle fixable using genetic editing using known techniques.
The more subtle biggest obstacles that I can think of of the top of my head is DNA methylation-related defects. If you are interested in a "quick soundbite example" of why this is important, I recommend reading https://en.wikipedia.org/wiki/Prader%E2%80%93Willi_syndrome (note the 25% of cases when this is what happens when there are by bad luck two maternal copies - and zero paternal copies - of ONE chromosome, similarly Angelman's syndrome); all chromosomes -- or any other chromosome, it appears -- is embryonic lethal in humans.
The underlying mechanism is: https://en.wikipedia.org/wiki/Genomic_imprinting
There is not any known way to effectively edit DNA methylation. It doesn't take star-trek level phlebotonium to get there (it's physically possible, just not with current levels of tech).