As someone that builds hardware all the time, your opinion is actually quite a common bias. The Idea that physical design (and aesthetics were important to Steve Jobs) can somehow reliably define the final technical form-factor is naive, and often leads to impractical products or vaporware.
Usually it is the common mistake that creates every camera that overheats, usb-c port that snaps off, or power adapter the size of a brick. Apple could have made the new iPad battery last another 2 hours, or make it 1.7mm thinner... They made it thinner, and provided less value to consumers in newer products.
In general, one MUST transition through every stage of the TRL or are bound to repeat the process from the start again at some point. Part of design revisions is figuring out whats possible (including physical volume constraints) with current technology, and whats appropriate in the projected market.
https://en.wikipedia.org/wiki/Technology_readiness_level
Notably, the physical volume of a battery is a physics constraint, and most of the mass of your iPhone is the battery (Steves team miniaturized everything else to reach the form it ultimately became.) The battery type is a requirement set by the desired function of the hardware, and chips slowly optimize for a given role (hence the trend of things getting slightly smaller/more-efficient, but compared to the battery volume it is negligible.)
Almost every business I've seen that prioritized the injection molded box first, has not survived to product launch.
One could disagree with physics, but then again most engineers will simply abandon that project. =3