You can do AWS without lockin. You can do messaging without lockin. You can do Postgres without lockin. You just have a generic way of integrating it with your apps plus a backup option. Then, you can leave at any time with lower costs.

Any kind of practice without such setup means you've decided to let the vendor control your situation ftom that point onward. Historically, from mainframes to servers yo desktop to mobile, this always led to less brnefits overtime where new, better stuff emerged that locked-in customers couldnt use at all or benefit as much as they liked. Those that avoided lockin could. Worse, some locked-in got hit with price hikes or even EOL'd products.

So, I think the default should be justifying a lock-in product rather than the other way around. Ive seen situations where it made sense. My comment mentioned one. It just rarely does esp today with so many cheap, flexible, and so on alternatives to commercial lock-ins.