I feel your pain on closeted cameras. I have a Nikon F3HP & a Hasselblad 600 (with 2 backs & 3 lenses) in storage. I keep getting urges to dig them out, but currently shoot with a Nikon D800 & don't really want to go back.
As to slides, while it is impossible to process Kodachrome yourself, Ektachrome is/was doable. I processed many rolls of Ektachrome 160T & 320T using the E6 processing kit. Many steps, but we had to get theatre rehearsal images out by the next morning, so overnight processing was necessary.
How long an image from a printer lasts depends on the technology. I have 16" X 20" images printed with an HP dye based printer that faded under fluorescent lighting
in under 6 months, but others using Epson's pigment based ink that are over 15 years old (in sunlight) that show no fading. I agree that silver based black & white is one of the least fade damaged technology, but pigment based color prints on archival paper can last quite awhile. Another advantage is as long as you keep the digital files updated so they are readable with the current technology, you can always produce a new print with the current technology (the same as with film, at least black & white).