1) Very few people use Blu-Ray or DVD players these days. Most are using streaming services (Netflix, Hulu, Apple TV, YouTube, Vimeo...)
2) 4K is quite common on YouTube and other sharing sites. It's fast becoming a standard.
3) 4K has enough resolution to handle a 50% crop and still be (effectively) HD resolution. This makes it wonderful for 4K capture, Full HD release, because you can crop, pan, digitally zoom, and software stabilize your footage, all in post-production.
4) Most of the better new computers come with free video editing software of some sort. For example, all Macs come with iMovie, which is directly compatible with their Final Cut Pro application. The latest 14" and 16" MacBook Pro computers are more than capable of editing multiple streams of 4K, and some of them can handle multiple streams of 8K.
YouTuber, musician, and singer-songwriter, Mary Spender, has perhaps one of the most interesting demonstrations of the power of new technologies including 4K video. She reviewed a new computer in this 4K video, but more than that, she created a music video with it and her 4K capable mirrorless cameras. Here's the link. Of course, she is a professional, and makes it look easy, which it is not. It takes a long time to acquire the skills to do this:
https://youtu.be/H3BGFWoqA9E1) Very few people use Blu-Ray or DVD players thes... (