If that's happening, it's either a calculated decision or the senior devs aren't doing their job. Someone should be communicating to management that the solution won't scale, with estimates of when it will fail or maximum load and the amount of time it will take to do it correctly.
Sometimes it's legitimately not worth optimizing something that will never need those optimizations. Sometimes management doesn't realize something needs to be optimized before it falls over. Sometimes management does make a bad call and doesn't want to optimize something that should be, but that's been uncommon (at least for me).
They will not believe you until actual issues happen. People in general are very good at dismissing problems that are right now biting someone else. You can see it all the time, even here in hacker news. And if anything, management is especially good at being confident that things will work out.
My senior experience is that if I see trouble that requires management intervention ahead, I communicate about it and then bail out. Trying to save it will just burn me out and as long as I am trying to fix issues, management thinks everything is ok and I am just stupid worrier. The issues must get real bad for them to be noticed and fairly often, it is best to let them go there fast.
Right. My point is that senior devs should be communicating the consequences of continuing down a rushed path. If management doesn't listen, they're making a calculated business decision (right or wrong).
If management is going down a rushed path and unaware of the tech debt piling up, that's a failure of senior developers to raise those issues.
Senior devs are good at communicating but management and execs aren't good at listening, they're good at counting beans. They don't care about tech debt because that's the issue of devs to work with.
Sometimes it's legitimately not worth optimizing something that will never need those optimizations. Sometimes management doesn't realize something needs to be optimized before it falls over. Sometimes management does make a bad call and doesn't want to optimize something that should be, but that's been uncommon (at least for me).