Personally I think the MBA will be EOL'd. There will be some blending of MBP 13 and MBA, but at the end of the day chipsets will become more powerful at roughly the same TDP (they could get more powerful and lower in TDP, but that just means an even MORE powerful one could be made at the current/target/usual TDP) so I think that there will always be a 1" thick machine to hold the hottest chips on the market.
They can make the slab thinner as more powerful chips come out, but everyone else will still be using the most powerful chips, so if they went that route they'd have powerful computers but still be out of the running performance-wise with the other makers using thicker chassis.
They can make the slab thinner as more powerful chips come out, but everyone else will still be using the most powerful chips, so if they went that route they'd have powerful computers but still be out of the running performance-wise with the other makers using thicker chassis.