We call that line of thought, and the ecosystem surrounding it, "old space". It's unnecessary, incredibly expensive, time-consuming, and end result isn't even very good. Unless...are these components being placed directly into space? If so...why on earth...erm...in space...would you do such a thing? COTS components can work fine. And no, I don't mean putting big lead blocks into space or anything silly like that. The internet has much to say about the way Falcon does it.
The ESA spends years, often over a decade, overengineering and certifying components. By the time they're ready for production, the private sector is already a generation or two ahead. A Starlink satellite can undergo a complete product lifecycle, from design proposal to end of life, in the time it takes the ESA to certify a single component, let alone a complete product. I really don't believe the ESA has the capacity to move past this either because it's bound by politics. What I mean by that is, you're never going to get out of the trap of having to design and build everything across 20 (or whatever it is) different member states, and all the logistical baggage that drags along with it. NASA has a similar constraint.
The private sector only has one real constraint: Whatever is good enough to meet all mission parameters with near 100% degree of certainty.
This is exactly why NASA, ESA, JAXA, and many other government space entities end up contracting with the American private sector rather than rely entirely on their own designs.