You can optimize almost anything if you put your mind to it. The question is, how much time, effort and money are you willing to put in to it?
If everything that needs to be said can be said on a single page, then creating additional pages just for the sake of having additional pages is wasteful and (dare I say it) less than optimal.
On the other hand, if somebody's cramming an entire website's worth of content onto a single page just for the sake of keeping it all on one page, that's not good for the visitor forced to wade through all that crap.
As to whether they can be "SEO'd" -- let's think about what it takes to optimize a page. The basics, in a nutshell:
- unique copy
- user friendly architecture/navigation
- no technical impediments to the spiders
- inbound links from other useful, legitimate pages
If the "template" comes with prewritten copy, then how unique can it be? If you have to rewrite the copy to make it unique, then what's the point of paying for the other pre-written copy? How likely is it that the webmasters of useful, legitimate websites are going to be willing to include a link to this one-page template site on one or more of their pages (without being paid to do so and no-following the links, that is)?
Edited by torka, 25 September 2013 - 09:58 AM.