OP here...
I will give Planet Bike fenders a look.
By the way, I have removed the broken fenders, as one suggested, and I keep riding. But I would like the protection I get from the fenders restored on my commuting bikes.

Another item: I have no problems with the front fender (only one of the two commuting bikes have a front fender) and the bus. I place the rack retention arm on the tire, immediately in front of the fender and not on the fender itself.

As for warranty on the SKS fenders: I don't know about that. I started a modification of the fender after it broke and haven't completed it. I placed a couple of layers of fiberglass cloth on the underside of the fender to mend it, but I haven't reinstalled it yet. Not only did the plastic fender break, but the stainless steel bridge for the rear wire stays also broke. I've started, but didn't finish, fabricating a new metal bridge. I doubt SKS would warranty a fender that now has fiberglass on it.

The bike that had only the rear fender came that way. I don't know if any of the previous owners had a front fender on it. It's a mid 1980's model Peugeot that has been converted to a single speed bike. The rear fender broke just as I started a ride that turned into a 53 mile Saturday cruise through the country and I listened to the maddening noise of the fender rubbing on the tire for about 52.5 miles. Since it wasn't going to do anything more than make noise, I didn't turn around and go home and get another bike...