> Gradual growth inevitably results in loads of technical debt.

Why is this stated as though it's some de facto software law? The argument is not whether it's possible to waterfall a massive software system. It clearly is possible, but the failure ratios have historically been sufficiently uncomfortable to give rise to entirely different (and evidently more successful) project development philosophies, especially when promoters were more sensitive to the massive sums involved (which in my opinion also helps explains why so many wasteful government examples). The lean startup did not appear in a vacuum. Do things that don't scale did not become a motto in these parts without reason. In case some are still confused about the historical purpose of these benign sounding advices, no, they weren't originally addressed at entrepreneurs aiming to run "lifestyle" businesses.

I think the logic is that good code is code which is maintainable and modifyable; bad code is difficult to change safely. Over time, all code is changed until it is bad code and cannot be changed more. So overtime most code is bad code which is scary to touch.

its not the law but a cost

software is unique field where project can be a problem that no matter how much money you throw, there is something that we can "improve" or make it better

that's why we start something small, a scope if you want call it that way

of course start something small or dare I call it simpler would result in more technical debt because that things its not designed with scale in mind because back to the first point

It is a law. The law of entropy.

Try as you might, you cannot fight entropy eternally, as mistakes in this fight will accumulate and overpower you. It's the natural process of aging we see in every lifeform.

The way life continues on despite this law is through reproduction. If you bud off independent organisms, an ecosystem can gain "eternal" life.

The cost is that you must devote much of your energy to effective reproduction.

In software, this means embracing rewrites. The people who push against rewrites and claim they're not necessary are just as delusional as those who think they can live forever.