The more people who mine the less valuable your mining hardware becomes, as the hash rate increase will lead to a difficulty update: it is a lottery that is designed to give payouts at evenly spaced time intervals.

You also now have a slightly old, very special purpose computer... it is like owning a three year old graphics card in a world where you decided graphics cards are not that interesting to own... what exactly are you "repurposing" it for? If it is some really awesome ASIC-based mining rig it might only be useful to mine Bitcoin.