I'm not sure that's entirely the case. I'd argue that someone who buys a 11" iPad Air with Magic Keyboard is making even more compromises for portability (smaller screen, less powerful OS, less connectivity). But I think the 2015 MacBook was ahead of its time, which hurt its sales. It was the first widely available commercial device with a USB-C port. There were no USB-C hubs available, and Apple's own USB-C adapters were bare-bones (and you needed separate ones for VGA and HDMI). USB-C itself was not fully finalized, so it took a few months for more capable third party hubs to emerge.I honestly think that people who are willing to compromise on everything for portability generally overestimate the size of their own demographic.
The number of people who truly want or need something ultra-portable at the cost of needing a dongle for basically everything is probably small and most people are better off with a MBA, which now at least has two USB-C ports plus MagSafe.

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