DuPont have legal rights to the constituent elements of the protector (not sure if it is intellectual property or something else) and I believe they sell these elements to other manufacturers or rebadge for other distributors. Other manufacturers may change the mix or add/subtract from the mix (e.g. to make it Woolsafe Approved) but the end result is much the same whatever you get. I'm pretty sure I am right in saying that Scotchguard by 3M is an exception to this.
As for acid dye blockers, I have used these a lot but there are problems. I don't know of any that are safe for wool; they tend to make the carpet wetter (penetrating rather than coating the fibres); customers don't understand them, expecting beading on the pile but getting rapid penetration of the pile - they then get out the 1001 and strip the protection. The product is good but needs understanding. For a belt and braces approach apply a regular protectant when dry if you are still around.
I now use Teflon and Teflon for Wool and get it from
www.restoration-express.co.uk. I also like Allure but it isn't Woolsafe Approved and as it is rtu it is pricey.