roundoak, This may not be 100% accurate as I am working from memory which is a little vague on Lee products in that time period. Sometime during that era the Lee company split into two companies one retaining the original name and one becoming the Lee Precision we know today. I believe the original named company continued to mfg. the hand tools the company was known for while Lee Precision started making more inovative tools, presses etc. that they are known for today. Unfortunatly the older named company went out of business probably due to poor sales and the hand tools went with them. Even then folks wanted faster production tools and were highly suspect of budget priced tools. To bad as I still have a couple of the hand priming tools, and loading kits and they work to perfection but they do it slowly.
Lee is still making the Lee Loader although they are phasing them out because the patents will soon expire. Once that happens anyone will be able to make them.
Only reason that I was ever able to figure for them to quit makeing the Lee Target Model Loader was, like a lot of things, there was a very limited market. People that have them like them, other people (I suspect that have never used one) can't seem to bad mouth them enough.