Well, these would-be "English teachers" will probably discover the challenges for themselves soon enough.
Anyone who simply packs up and moves to a foreign country without a very solid plan or a job offer is a bit irresponsible in my view, or they will have to be prepared for a rather failure. Plus - I imagine there is no guarantee at all that you'd get a Russian work visa just because you fancy living there and teaching...

For somebody young, who want to learn Russian at the same time as teaching English, the low salary might not be so much of a put-off.

Some of those who envisage themselves as English teachers in Russia may be planning to do it on a voluntary basis, as part of some project etc, without pay.
I read a story about somebody who was a missionary for some kind of church, who offered English lessons and a while into the lessons, the person started evangelising her pupils! They actually got some converts to their church that way - I forgot what denomination it was.

The American organisation called "Peace Corps" was discussed in a thread about criminal case in Ukraine, used to offer English lessons in Russia for free, however they were up to some other activities too, and got banned in Russia. The British Council offers English lessons too, although I think, at a price.
Plus, people who, like Irina says are on a tight budget might want to simply use whatever books or CDs they can get their hands on cheaply, or free online resources.
In this day and age it IS possible to learn a language without a teacher.