The developer edition was mentioned, and that runs Electrolysis already. Even the normal release does if you don't have incompatible plugins.

(FWIW, before electrolysis Firefox was unusuable with many tabs for me, now it is perfectly fine, so either I made a random setup change at the same time, some other optimization landed or it actually helps)

Yeah, to me it seems like a mistake given that such a high performance penalty will likely be incurred, and given the existence of Rust which could address a number of the security problems for which the multi-process model was devised in the first place.

Note that e10s currently only splits the browser into a content process and a browser process. I don't think they will ever move to 1:1 tabs per process.