In the last ten years I have also seen 'backplane' be:
* A protocol for helping web widgets on a page communicate and share data https://openid.net/wg/bp/ . We used to support it at Livefyre to interop with certain Janrain products, but the ecosystem wasn't so big at the time. It wasn't under OpenID at the time.
I remember being at a hackathon of theirs (the Lady Gaga backplane) years back and seeing dozens of what looked like Herman-Miller Aeron chairs all over the office. Maybe they got them for cheap, maybe they weren't actually Aerons, but also maybe this pretty small (I don't actually know how many employees they had..) startup had a couple tens of thousands of dollars worth of office chairs
The cost of a good chair is nothing compared to other expenses like salaries. Aerons aren't my favorite chair but I sure as hell don't want to work for a company that makes me sit in a terrible $50 Office Depot chair.
Besides, you can get Aerons for much cheaper than retail if you look.
Even if you give zero shits about your employees, the $50 office max is going to fall apart fast with daily use. HM sells somewhat stripped-down cheaper versions of certain models specifically for the bulk office drone employee market and in bulk the pricing is competitive with other makers.