Unfortunately, chips EOL all the time, charge pin-outs, and the temptation to in-house an integrated SoM solution may add hundreds of thousands to the cost. If you are not moving >3m chips a quarter, than you are still vulnerable.

We also had to violate the Design for Manufacturability guidelines to adapt to the shortages and part skelpers hitting JIT lines. Even today, we incur a questionable 12 USD labor cost on every product to ensure a generic carrier PCB drop-in population option is always available (0.1" pins 1980's style).

Training slide deck: "Rule #21: No unicorn parts, and no excuses"

We dodged the CM4 choice luckily due to my concerns, but still were tagged by a proprietary missing RF module needed for legacy system interoperability. The vendors lied about inventory levels, and kept the order tied up for years before the spools arrived.

Best of luck, =)