Not to negate your core points but almost all the HW engineers I've worked with who are experienced absolutely consider sourcing and availability in the decision making process.

It was a reason years ago Maxim's ICs were almost always on a "never design in" list since obtaining them was near impossible in reasonable time frames.

Most "seasoned" HW engineers who are working lower volumes verify availability with distributors and for high-volume (i.e. 100K units+/yr) work with sourcing people internal to company to get commitments for key ICs.