There has been a fantastic response to this thread and I've really enjoyed reading everyone's responses. I din't get a chance to get involved yesterday as I was working a very long day so thank you to everyone who expressed their thoughts.
Responses are clearly subjective, including mine. The 10 times easier title for me is related to time devoted to writing and prduction. Increasingly the two disciplines are difficult to separate. Perhaps the modern songwriter is both a writer and producer and therefore the two shouldn't be viewed separately. There is great satisfaction to be gained from presenting a song that's is purely your own, from writing to musicianship to production.
It's not that I don't know how to produce or that I'm really slow at employing the processes, rather I fixate on the smallest details until I achieve what I want. I hardly ever compromise or make do. There's definitely an element of OCD here for me. On the other hand, I can decide to write on almost any given day on my first instrument (guitar) and nail the song very, very quickly. I can also do that on piano though I am not as accomplished as I am at playing guitar. I find the songwriting part easy. For me, there are far more elements involved in a successful production than there are in writing a song. There are far more choices and decisions to be made.
I agree as
@kafla said, it's all in the writing. You must begin with a great song. However, that's not my point. I might decide to produce a song for someone though I don't think, it is well written. I'l still lock horns with the production and make that song as good as it possibly can be, even improve upon the original. It will still take a tremendous amount of time to finish that production.
Everything I read about this does suggest to me that many modern songwriters are both writers and producers and that the two disciplines are difficult to separate, unless of course, you employ someone to produce for you.
The modern home writer producer has so many tools and virtual instruments at his/fingertips. Decisions, decisions, decisions! Perhaps learning to discipline yourself is a great asset here. I acknowledge that the production time can be shortened depending on the genre of music that is being produced.
Anyway, this is very subjective. I still believe that for me at least, songwriting is 10 times easier than production.
Paul