Related: designer Thomas Thwaites had the same thought and created a toaster from scratch, starting with iron ore: https://news.ycombinator.com/item?id=14942190
Sometimes it's equally surprising to me that some people have so much time on their hands to pursue things like this...
Time into which they have to fit eating, cooking, cleaning, showering, laundry, shopping, commuting, exercising, childrearing, family, professional development, dating, socialising, home maintenance, personal paperwork, pursuing hobbies, and relaxing.
You can have a lot of time for one of those - if you're willing to prioritise it over all the others.
and the difference between that diy contraption and this fancy old toaster is like a difference between a skateboard and a car https://www.youtube.com/watch?v=1OfxlSG6q5Y