I can absolutely guarantee there is no shortage of trailers in the world, perhaps just a shortage of new trailers.  

There certainly are a lot of junk trailers that should be scrapped, but maybe just as many old trailers that aren't really junk.

Something that might or might not work for you, but for me, in at least 4 cases I can remember, I've never had it fail...

Look up several local yacht clubs, boat storage facilities, government/public parks that allowed boat storage, etc. in yur area.  Give them a call (don't waste all your time driving) and ask if they might have something.  Places like this almost always have some back weedy lot full of derelict boats and trailers.  For the price of packing the wheel bearings (almost ALWAYS required), new tires and new bunker boards (and adjusting/replacing an occasional roller,etc.) I've always been able to find a cheap or no-cost trailer that would work.  You might even have to volunteer to dispose of the boat that is on the trailer.  Maybe a visit to the dump and $50 fee to shove it off the trailer.  And even if you have to replace wheel bearings, that really isn't a very hard job.

Truly, the hardest part of this exercise is the paperwork, often very dependent on state title/registration/trailer weight regulations.  The light trailers are sometimes not that bad wrt regulations.  But check with DMV or whoever even before taking a trailer that you later can't license; even ask them about maybe "adding new bunker boards, or touching it with a torch" so you can declare the trailer home made.  Some bureaucrats will actually work with you if you tell them what you are doing.  Finding an actual owner is usually impossible, but one time I actually did and got the (no cost) paperwork completed by mail. Try to convince anyone you can - either owner or at the place where the trailer is stored to sign some sort of paper that says they either sold you the property for $1, or even if they didn't own it, that it was abandoned and given to you.

If you do get one of these older trailers back on the road you'll have done everyone a favor.

I've had much success with these methods, and have always found something very good that suited my purposes very well, not rusty junk.  Even with new tires, often on the road for less than $100.

Oh my Bubblehead, what a great idea!  Thank you.  I started looking for used ones too, but  an "abandoned" one is brilliant!  At worst case, I can find one to hold me over until the supply chains open up.     

I bought a used jet ski trailer on craigslist ($160) put a longer tongue on redid the bunks and it works great. Better than others since the boat rides lower and easier to launch. Steel but I don't see the need for al with a boat the weighs just over 100lbs. I pull mine with a Honda crosstour. Email me if you want pictures [email protected]   

   I suppose it is likely that I ordered my Trailex Trailer before this shortage. I had anticipated a very long wait but I received it within a week. I recommend ordering it. Maybe it will show up much sooner than anticipated. 
-Greg