But the US is not the only first world country.
I live in one and my salary is a little less than 30k and I'm not a junior. My junior colleagues are at around 20k, so for them it's actually 10%.
I never expected a first world country to pay that little. I live in New Zealand. Your colleagues are earning less than our minimum wage.
So apparently first world is not the same as "high income". In that case I would buy something from Taiwan.
A first world developer salary would be much higher than $400 x 10 = $4k per year.
At a moderate $80k USD developer salary, the laptop costs only 0.5% of that. And this is the main tool you depend on to earn an income. For an underpaid junior developer earning $40k it's still only 1% of their income.
10% of an average developer salary is something like $8k per year. What laptop costs $8k per year? That's $40k after five years. Are you confusing a laptop with a new Mercedes or what?
Laptops are a business expense for a developer. This is how you need to think about it.