You are awesome for sharing. For a while, Disney was selling slip covers for like $1 a piece and $3 shipping if they had extra covers. I was able to get a couple off of them, but not all. I'm missing Pony, Winnie the Pooh, Toy Story 1 (original cover, not Woody), and Sword in the Stone.
I know the feeling of constantly changing mediums. Growing up my aunt got me and my sister the VHS tapes. Well she had a kid and moved out on her own, and guess what? She got to keep the movies. I started a collection with my best friend that I lived with for a really long time, I let her keep the movies when I moved across the country. Now thankfully, my boyfriend has no interest in keeping my movies if anything ever went sour. I have most of the collection on Blu Ray now, including 6 movies in 3D. Honestly, I hope 4k stays off far far into the future. I have no desire to recollect my movies. Although I have repurchased a couple of the releases just to get the digital copies (if the price is good enough).