microbiology - Is it plausible that eukaryotic organelles like flagella and cilia are the result of endosymbiosis with spirochetes?

This was a claim by Lynn Margulis explained over at this link.

The sense organs of vertebrates have modified cilia: The rods and cone
cells of the eye have cilia, and the balance organ in the inner ear is
lined with sensory cilia. You tilt your head to one side and little
calcium carbonate stones in your inner ear hit the cilia. This has
been known since shortly after electron microscopy came in. Sensory
cilia did not come from random mutations. They came by acquiring a
whole genome of a symbiotic bacterium that could already sense light
or motion. Specifically, I think it was a spirochete [a
corkscrew-shaped bacterium] that became the cilium.

And why would our bodies incorporate spirochetes as part of our basic functionality?

There are many kinds of spirochetes, and if I’m right, some of them
are ancestors to the cilia in our cells. Spirochete bacteria are
already optimized for sensitivity to motion, light, and chemicals… If
I’m right, the whole system—called the cytoskeletal system—came from
the incorporation of ancestral spirochetes.