$10,775 over a period of 11 years. I 'only' own 850 games, so I'm probably at the high end of price-per-game. I'd say that about 90-100 of my games are retail codes bought elsewhere, so I'd add on another $1,500 to $2,000 there making it around $12,500.
It's a bit of a downer seeing it all laid out like that. But no surprise really. This is what can happen when you focus on building a digital collection rather than focus on playing the games you own. It got away from me in the early years - from 2007-2012 or so I was buying like a madman. I probably owned 600 or more games by the end of that period. So at least I've tapered off. Someone said that the old spend was before April 2015 (I've got a total of €9,535 old spend).