Hi Tim
First of all, you're right that having a page with dynamic content, or having a page that is constantly updating, may help your site to rank, as the page could be seen as "fresh" quite regularly.
However, not having a frequently updated page does not mean that your site will be crawled infrequently, nor does it mean that your page cannot rank.
If you have a sitemap submitted to Google/Bing, chances are that the search engine is going to revisit your site very often. You can see here that the last Google cache for that page is the 23rd of April, which isn't that long ago. This is a useful guide on how you can increase crawl rate.
With that being said, a far more influential factor towards rankings and why your site may be falling will be the links pointing to your page. Looking at the open site explorer report for that page, I can see a number of links that may have passed value before but would be in line for a link devaluation.
First of all, I can see a few forum links that contain your URL in them, such as this and this. Nothing wrong with having those links there, particularly if you were troubleshooting, but I've seen quite frequently that forum links will lose any 'worth' that they once had over time. That may be one reason for the drop.
There's a couple of links here and here that also look quite unnatural. I can see why Google would devalue these links - if you look at them from a human perspective, they look very artificial and have some very optimised anchor text. I'd keep an eye on links like these - I can't imagine Google would be thrilled seeing them in a link profile.
Finally, you also seem to have a number of regional microsites, such as this and this pointing to the page you provided. Now, the content on these sites is informational, if a bit sales-y, but the wording is only slightly different from site to site. There's not a lot of value in this content and as such it could be constituted as thin. Without the content offering much worth to a reader, it could also be a site that has had its link devalued - not penalised, just devalued, I hasten to add.
With all those links devalued, therefore not passing the strength that they once were, this might explain why you've fallen to #11.
There's no major concern here and it doesn't mean that you should remove these links - but if you want to regain your ranking I believe you would need to replace them with higher quality links. These can include links from articles or features on other articles that tap into the site's expertise. It could include creating content or a resource centre on the site itself that would encourage people to link to it or share it on social media with friends. There really are a number of ways to accrue higher value links - but what differentiates a higher value link from lower ones, at least in my eyes, is if the link is contextual to what you are offering on your site, it offers value to the reader and it can be seen and shared by an active audience.
This is based on my expertise and certainly does not constitute as fact, but that's just how I see it. Hope it helps you out a bit and if you have any more Q's just let me know.