I'm not sure that the portability/power tradeoff is suitable for the mainstream. Specifically, I am referring to the value proposition of the machine.<p>There are three reasons for this - firstly, the mainstream cares a lot about price. Apple's new machines are expensive, and it stands to reason that a portion of the added expense is in the engineering efforts required to e.g. redesign the SSD card factor, battery, casing etc) to accomplish the size and weight.<p>Secondly, Apple's BTO upgrade pricing is extremely high when compared to off the shelf parts. The lack of upgradability, and with respect to batteries, serviceability hurts mainstream users, but they may not notice this at the time of purchase. I know many users with Macs who I would would consider "mainstream" (i.e. not technophiles, people that don't work in IT industries etc), and the vast majority have either upgraded parts in their machine at some stage via a local computer store, or wanted to do so in preference to replacing it outright.<p>The old MacBooks and MacBooks Pro could be purchased with minimal or required specs at the time of launch, and then upgraded with off the shelf, standard parts by basically any mediocre technician, for a fraction of the cost of buying a new machine and selling the old one on the second hand market, giving them another year or two of usable life. The new Macs cannot, and Apple isn't exactly generous on specs for the lower end models (RAM perhaps, but SSD and CPU not at all).<p>Third, because of the lack of upgradability, the second hand market for Macs is now extremely fragmented and difficult to navigate. Those people who buy second hand Macs (myself included on occasion) have a much harder time now with the various unchangeable combinations of i.e. 2GB ram / 128GB SSD. If you're looking for an Air with 8GB RAM (almost a necessity these days) and a 256GB or 512GB SSD, you'll be looking for a long time or paying a big premium - whereas a non-retina Pro of similar vintage can be purchased without fear, and upgraded easily and cheaply - often to specifications well beyond that ever available with the machine at purchase. 2TB SSDs, anyone?