I frequent this forum quite often but have always been reluctant in participating in the discussions.

Anyhow, I thought of giving it a go today :)
So basically I am an academic writer. I work with one major writing company. I cannot work with any of the other major companies for the simple reason that they don't hire ESL. Coming to the topic of discussion of this thread, I think the answer is, 'it depends'. I have been working as a full - time academic writer since the last three years and my earnings haven't been great. In a typical month, I earn anything between £200 and £1000 before tax (and on some rare occasions, I manage to earn £2000), which isn't great and cannot provide for a decent living. But it is fine for me considering that I am a full time mum and my husband earns very well. However, I have heard cases (on internet forums) of full - time writers earning over £4000 a month.
So I wouldn't say that the prospects are bad in this career. I relate my low earnings to two factors:
(1) I work for just one writing site so the work I get is relatively less, and
(2) Even from the work that I am offered, I only take up work that I am very confident in (I have only written on subjects that I am specialized in and have never tried other 'related' subjects).
So basically if you work with a number of writing companies and can write on a variety of subjects, there is a possibility that you could have a great career in academic writing :) Best wishes for all your future endeavors.