I don't think TK specifically mentioned iPad but the relevant quote was;
I'm not too a big fan of tablets either, but whether we like it or not, its going to be the way of the future. Windows 8 is schedule to come out this year with the touchscreen interface, and the mouse is going the way of doo-doos, if not now, soon. Their capability is still a bit limited compared to desktop PC, so the game market there is almost like the 80/90's desktop game market where great games could be developed with a very small team. It probably won't be this way for too long, the computing power of tablets and even smartphones are fast approaching that of desktop, so we figured its better to be in it now than later.
My first reaction: Don't panic. It's not going to happen today, tomorow, next week, next month or next year.
My second reaction: I'm probably typing and posting this using the last PC I'll ever buy. The same applies at work. My current PC at work will not be getting replaced.
My third and over-riding reaction: It's HIS business. He knows his game, his market and the macro market better than anyone posting here. The timing of his switch requires good judgement so I wish him well.
For the record, I don't like tablets either!