Imagine you're asked with building, say, a train network within your country. Domestic regulations demand that, because other countries are not certified up to your country's safety standards, you're not allowed to import any foreign technology from outside your country.
So - in order for you to build that train - you'd need to wait for industries to set up to build every single component up to local standards. And if nobody sets these industries up to manufacture the components you need, you'll have to build it yourself, somehow.
You'd rightfully call this out as protectionism. And the worst part is not even the protectionism - the worst part is that you'll likely get no trains, because in practice nobody except a huge incumbent company can build all the components they need themselves, and huge incumbent companies often have no incentive or no agility to do so.
So - in order for you to build that train - you'd need to wait for industries to set up to build every single component up to local standards. And if nobody sets these industries up to manufacture the components you need, you'll have to build it yourself, somehow.
You'd rightfully call this out as protectionism. And the worst part is not even the protectionism - the worst part is that you'll likely get no trains, because in practice nobody except a huge incumbent company can build all the components they need themselves, and huge incumbent companies often have no incentive or no agility to do so.