nobody would want to be stuck nowhere without any fuel
regardless petrol or diesel, still inconvenient for any drivers
though euro 2 is easily available but seems latest diesel tech is always preferable

Incorrect. It's newer common rail direct injection recommends Euro 5 fuel as the engine operates at complex magnitude and controlling precise curling to ensure minimal smog. They can still run conventional euro 2.
Its just like smoking. You know it's bad. But the side effect differs to people. Preventive measures like running injector cleaners etc can help prolong the life span but does not ensure longetivvity.
You rarely see diesel cars overhaul due to long mileage because they don't run like normal petrol piston ring. The higher the pressure, the greater the seal.
No such nonsense. Just pump in euro 2. Nothing is going to fail. Don't be paranoid, even fifth gear also confirm that diesel engine can run on petrol. If you accidentally pour in gasoline, don't worry. Top up more diesel. You will feel your car run smoother but slight less power. After bleeding out all the gasoline, it will just run like normal.
I think everyone here has a misconception on modern diesel car. They are not as taufu as you think. You can run a full tank diesel on idle till it runs out of fuel under the hot sun, and still you won't risk on getting your engine gasket burn. Euro 2 is like smoking cigar, while euro 5 is like vape. I can say the most fragile part of the modern diesel engine is the injectors. Because they operated at high parameters and electronically controlled by fast pulse.