Because when I lived with my parents I had a NES and a Super Nintendo, then I left home but my sisters wanted to play and I left the games for them. Went to live with friends and had to buy another Super Nintendo and new games. Then the N64 came out, and the Play Station, bought those but then I moved again and my friends asked me to leave the games there, and the cycle tended to repeat. I didn't lose any console except for a NES, but I lost most of my games because back then I didn't care enough to bother getting them back, I just bought them again. Then I briefly moved to Argentina and I asked my friends to send all my stuff to my parent's house (for the most part they did, but they did steal stuff, like a Casio keyboard and a refrigerators). Then when I moved where I live now, I went to my parent's house where they stored it all, and brought it here where I can see it all together finally. There are things I don't mind having collected impulsively, like books or music, but when I saw all the consoles together I felt like an idiot. I should have been smarter with money.
And yes, I'm selling those. I'll try so sell them directly to buyers, too. That's better money.
When you think about it, if you mod a Wii U, that machine alone will do everything the other consoles do. Mod the PS3 and then you don't need the PSX or the PS2. Then you need just two consoles for all your retro needs.