Why is the Mars rover's wheels made of a metallic material instead of a less rigid material? ?

Hmm ... dozens of engineers and scientists worked on the design of those wheels. Several more reviewed the designs, several times. They recognized the total system constraints of weight, shape, size, efficiency, effectiveness and costs. They discussed many different definitions of "best".  They might not have come up with the best design from your viewpoint, but I'm sure it was pretty damn good in their collective professional opinion.

durability under mars cold, heat, dust and rock  storms corrosive gases,

Metal might be more durable and flexible than plastic or ceramic. Plastic would melt, ceramic crack. I can't think of another substance, except maybe something lightweight, but then, it might float away to easily. 

They are NOT trying to insulate themselves from the ground. They want to feel every bump and hollow. That tells them stuff.

We on earth can get out and handle the ground and feel how hard each stone or puffy spot we ride over. We are bored so look for a smooth ride over gravel or swamp.

. They do not know what is there so are not trying to adjust for comfort.  They want to know what the ground is.  Metal rim is much lighter than adding a rubber tire that has no air in it so it would always be flat.   Hazard lights are added weight and AAA is not coming out to change the flat tire.

You can refuse to believe anything you like.

If you think you know better than NASA engineers, get a job with NASA and show them.

Bear in mind there is no one riding on the vehicle and it travels so slowly that suspension and a smooth ride is irrelevant for its instruments.

They are not meant to last for more than a few decades, but it was a better option given the condition of Mars. 

You asked this question three weeks ago, and I gave you an answer as did other users.

Please review those answers.

Well, that's because you're a clueless knob.

Curiosity had lighter wheels. They found that the terrain caused far more damage to the wheels than they expected.

As a result, Perseverance got stronger wheels.

Plus, as the rover has six wheels, the proper phrasing is 'Why ARE the Mars Rover's wheels...'