Yup... it's almost impossible to go onto the D&D website, click on the Product Info dropdown, go to Tabletop Games, and then see DnDClassics (PDFs) in a list of six things. No one will ever find it! And then if you click on that link, it's inconceivable that it'd take you to a new site that lists seven distinct Settings and six distinct Editions from which to find product. How could we possibly expect a new player to comprehend all of that?
I only found out about D&D classics very recently.
It's also quite non trivial to convert older stuff. Way beyond that of a new DM. There are huge gaping holes in the 5e DMG (traps, diseases, etc) and tons of missing monsters, especially from 3e.
I spend about 6 hours a week converting one 3e module to 5e, I've been doing it for three months.
I'd definitely like more adventures for 5e I can just pick up and run, especially those of pathfinder quality and not HOTDQ quality.