Because that's some trash.

Or as IGN seems to understand it based from that interview:

"However, Microsoft executive Phil Harrison, in an interview with Kotaku, has some potentially bad news. The aforementioned 'fee' to play games on a second account? Full MSRP. So unless you want to use your account for your entire family, you'll be dishing out an extra $40, $50, $60 for siblings or friends to try out new games. Harrison did tell Kotaku that his company plans to allow gamers to 'trade' their used games online somehow - though declined to get into further details."

Bye bye LANs? Sheesh.

You know, I already had no intentions of purchasing either a PS4 or the new Xbox until next year at the earliest, but the details for this thing are really doing a great job of making me not want it at all.