Nope, it's a French loan word. In English and French, a bloc is a political group. The original French meaning was a block, like a block of wood or cheese, and that meaning is still used, but came to also mean political group or alliance at some point. When it was imported into English, we only kept the political meaning since we already had block.

https://www.etymonline.com/word/bloc

Like all quirks of English the French are to blame.

Yeah, I'm not sure I'd credit the economic system with repairability or blame it for unreliability.

To use WW2 as a measurement point: western allied vehicles tended to be extremely repairable. Eastern allied vehicles were also extremely repairable. Western vehicles tended to have closer tolerances for parts, meaning a part could be damaged easier. Eastern tended to have simpler parts, meaning they could be repaired. Western vehicles were geared towards modular components and ease of replacement, so you could swap an engine in 20 minutes or spend an afternoon building a new tank out of two that had been destroyed, even if one was a different model. The Eastern tanks tended to have a more intensive overhaul process, and less shared components between models.
Nazi machines were a shit show with custom parts, low repairability, and poor workmanship. I have no idea why people give them credit for good engineering. Jets are cool, but useless if you can't fuel or fix them. Advanced engine systems are great, but you can't repair them and they explode under stress. Ornate and bespoke parts are cool until they're produced by slaves who do the minimum to avoid death and it warps, leaving you without hope of replacement, no ability to scrap the damn thing, and an enemy who can repair their tanks by either sufficiently motivating a tree trunk into an axle or by using three cars to build a new tank to factory spec over lunch.

You've got America turning car manufacturers into weapons builders: stellar. Mass production and modularization with a skilled assembly line.
You've got the UK having people build machine guns in their basements from simple plans. Wicked little death traps.
You've got the soviets dictating material allocation and design priorities.

The common factor to the good design is the workers distance to design feedback.
The easier it is for a person doing the work to correct how the work is done, the faster the design will iterate and the better it will get.
That feedback loop can be good or bad regardless of the specific economic model.

Hell, duck tape was the result of an ammunition factory worker thinking the tape they were using for ammo boxes was stupid and would get her sons killed, so she wrote the president. He didn't understand in the least, but gave it to the war production board and told them to Fix The Problem, which they did.

Conclusion: if you want good shit, have the people building it tell you how to fix it. Repeatedly.
And don't use fucking slave labor, it's unethical and bad manufacturing.