I can't believe anyone is even suggesting that Supes is more durable than Cap's shield. Cap's shield is the penultimate standard for durability. Only three things have been able to break the shield:
Thanos w/ Infinity Gauntlet
Doom w/ pre-retcon Beyonder's power
Thor w/ Odinforce
The power listed above is about as top-tier as you can get and Superman can and has been hurt by far less. Cap's shield has never sustained damage from anything less than the above. And the continued belief that Thanos only used the Power Gem during the heroe's fight is ridiculous. He throws people into time, morphs them into glass, reduces them to cubes, etc. How the f*ck do you do that with only the Power Gem? The only thing he cut off was the sensory input and omniscience that the IG would have provided him. This thread is a joke.