Radio Shack hasn't completely gone away.
They're presently offering an
Adventure Kit: 30 Days Lost in Space (https://www.radioshack.com/products/inventrkits-adventure-kit-30-days-lost-in-space/) which features an Arduino Hero Board and a series of experiments dealing with Coding and Peripherals.
Quote from: the Page
New Sci-Fi Adventure Kit Teaches You Advanced Coding and Circuit Skills in Only 30 Days!
Fortunately, for those who enjoy the educational value of kits, Heathkit is still in business as well. (https://shop.heathkit.com/shop)
Many of the former Heathkit projects are available on ebay. (https://tinyurl.com/32yha97k)
Many of us made use of Electronic Kits and related Educational Materials during the heydays of the 70s, 80s and 90s.
It is good to see that they have not completely disappeared.
Heathkit Schematic and Manual Archive (https://www.vintage-radio.info/heathkit/)
Whatever Happened To Heathkit? (https://www.electronicdesign.com/technologies/analog/article/21801229/whatever-happened-to-heathkit)
Other Sources for Heathkit Technical Information (https://duckduckgo.com/?q=Heathkit+Schematic+and+Manual+Archive&t=h_&ia=web)
Sources for Radio Shack Product Technical Information (https://duckduckgo.com/?q=Radio+Shack+Kit+Schematic+and+Manual+Archive&t=h_&ia=web)
Do any of you remember the Radio Shack P-Box Kits? (https://hackaday.com/2018/12/14/retrotechtacular-remembering-radio-shack-p-box-kits/)
The Manuals and Schematics for those are available here. (http://my.core.com/~sparktron/pbox.html)
The schematics for those kits are relatively simple and can easily be "rebuilt" with common components.
Some of the circuit diagrams were quite unique.