Is it possible that all existent bacteria once were commuting organelles?

TO BE ADDED:
FROM WORD: If we define all "organisms" that are dependent upon eukaryotes by frequently visiting them as commuting organelles, then there today exists quite a few. They are all related to archaebacteria or eubacteria, and it has therefore been assumed that they originate from such organisms. But the fact can be the opposite, that the bacteria were all commuting organelles. 

OM commuting organelles i dag EGET?  

TEXT FROM QUORA, OET:

As explained in the previous posts, the organelles that became bacteria were for a period commuting, before their host became extinct. For some of them the period of commuting could have been quite lengthy, and it seems that some are commuting even today. There are reports that methanogen organelles (in the reports denoted "methanogen endosymbionts", but I prefer the name "methanosomes") coevolve with archaebacteria in the environments, explained as substitution of the organelle with environmental organisms. In “Multiple Acquisition of Methanogenic Archaeal Symbionts by Anaerobic Ciliates” it is concluded that substitution has taken place repeatedly, i.e. repeated endosymbiosis, which is far from the conclusion that endosymbiosis is an extremely seldom event. Nick Lane argues that “it’s probably relatively easy to come up with something like a bacterium and we will see bacteria almost everywhere”. But complex life may in his mind be found only on Earth. In his mind, the acquisition of mitochondria is the event that created complex life, life that could potentially become intelligent and make themselves known to the universe through radio signals. Lane sees the negative results from the SETI project as evidence endosymbiosis is a very improbable event. I agree with him that a creation of mitochondria from a bacterium is improbable, so improbable that it never happened. But organisms that are usually called bacteria are entering organelles all the time to cooperate with its host. The “Methanogenic Achaea” mentioned above is one example. With the Organelle Escape Theory it is the “A organelle”. It is a “commuting organelle” by the OET terminology. They are not only entering their host. They are also exiting. Such exiting is the source of all bacteria. I see them as bacteria when their host or hosts are all extinct.

There are also examples of present commuting based upon the B organelle. One example is the Legionellea pneumophila. They thrive in amoeba and normally reproduce inside them. They are aerobic, i.e. they could potentially have given aerobic metabolism to an anaerobic host. So what is it that makes endosymbiosis so improbable, according to Lane?

In the OET view of cellular evolution Legionellas are example of commuting organelles that evolved in parallel with the stationary variant, that became the mitochondrion. It is the easiness of crossing the membrane for small neutral molecules that has made the commuting variant obsolete and just appearing spuriously as Legionellas.

SJEKK
With OET the coevolution of organelle with environmental organisms would instead be explained by update of the environmental organisms from the host, as all the bacteria were once commuting organelles, but today only a few have hosts that could supply new variants. It is with OET, regarding the organisms as commuting organelles, much easier to explain the observations in the article.