If someone wanted to revised the Royal metal uprights, they would've done so already as there's no need to wait for patents to expire. But think about why the Royal metal uprights were discontinued in the first place. If you ask me, they're just outdated designs. I used to vacuum for a furniture store with a commercial Royal metal upright that was mine before but gave to them and regretted doing so. It actually got tiring to use. There were belts that had to be changed. There was no hose and attachments on-board. And I actually cracked the fan despite it being metal. I remember there was one other thing that I broke on it but I can't remember what it was. The same went with a commercial Sanitaire Widetrack that was also mine before but gave to them as well and regretted doing so. Had to change the belts out, broke the fan, and had to constantly get the Shop-Vac the store had out to use the hose that the Sanitaire or Royal couldn't get to. Not to mention the shake out bag on the Sanitaire blew out alot of dust. All of that would've been avoided if I had used something like a Windsor Versamatic or a Lindhaus RX Eco Force for example with geared belts, on-board hose and attachments, bypass design, multiple filtration, etc. Stuff that most consumers and commercial applications want to have because not all of them would feel comfortable fixing vacuums themselves or visit a vacuum store to wait and have them fix the vacuum.