Hi Alan,
We're in a similar position. A site that had 12,000 views a month a year ago now has 6,000. There's lots of things that we are doing but one of them is rewriting that content.
It is mind numbingly boring writing fresh stuff about one almost identical product after another. So I've taken a few approaches to make it easier.
First; I don't rewrite pages. I'm treating all my pages with 2 - 300 words as introductions. So I go through and add a specific paragraph or a type of link. It's generally a job that can be done in a few hours for my 100 product pages and normally delivers 2 - 5 positions on SERPS. Then I leave it for a few weeks - burnt out with the effort. It also slowly adds more structure and makes pages increasingly valuable ![:) 🙂](https://moz.com/community/q/assets/plugins/nodebb-plugin-emoji/emoji/android/1f642.png?v=4jds23d1a2r)
Second; I spend time making new good content. It's fun, its fresh and I normally get an immediate dopamine buzz as I get some more traffic after posting it in a newsletter or on a social media site. Being rigorous in linking back to my product pages helps too,
Third; I do it by the numbers. I've looked at 7 years of search queries to my site (so lots of stuff before 'not provided') and matched that up with moz difficulty and google traffic estimates and current serps positions. So when I do spend time on a page I calibrate the amount of effort specifically to the potential payoff.
Finally - given that your pages are likely to be similar to mine - we both have competitors who have access to the same content and write similar stuff I continually look for an angle to differentiate my page. For you it may be - other companies in the building, famous people who worked there, closest Deli or starbucks. This I think works, still experimenting, because if I was google looking at a keyword space i would compare the top x pages to each other - say on word usage. The ones several SD from the mean in word variation count (all other factors being equal) are likley to be saying more interesting stuff.