Are Top Brass afraid to make changes in Army regulations, customs and courtesies?

You lost me at this one: "Standing at attention and parade rest when addressing superiors."

You might want to look at history before saying leadership never makes changes. When I came in the service uniform had a winter and summer version. Change was made on a certain calendar date and it didn't matter where you were stationed, it might be 90 degrees out, but the calendar dictated wool. Your cotton fatigues would be starched, but they finally changed that to allowing permanent press uniforms. If you were a trooper in the southwest during the Indian Wars you would wear wool uniforms all year long.

Can you provide some examples of what you consider rediculous so that we can have an informed discussion?

Change is difficult. I worked for 6 year as a DAC trying to make changes that would improve efficiency and quality in the transportation business. It was hard. Even when we had Commanding General support, change was often completely and successfully resisted. Consequently, some senior officers and civilians choose the "if it works, don't fix it" approach to management. The key word is "works." Some processes and things work quite well and truly don't need fixing. Often things work because of exceptional human intelligence or brute force making them work. These things and processes should be fixed for the good of the Service Members and Civilians who use them and cost savings.

Another factor in preventing change is the civilian workforce and the constant rotation of military officers. DACs tend to stay in one location and one job for many years. Officers are assigned to command for 2 years and in a single location for no more than 4 years in general. If the DACs believe an officer is attempting to make changes detrimental to them or the organization, then they can slow-roll the change and outlast the officer. In this way "the way we've always done it" is perpetuated and new ideas are successfully resisted.

Finally, there's organizational inertia. Large organizations such as an Army Major Command or the entire Department of the Army, are more difficult to turn than the Navy's largest Aircraft Carrier. Once the organization is headed along a certain path toward a mission-vision-goal set, it is very difficult to steer in a different direction quickly. Changing the strategic direction of these large organizations takes time, patience, and persistence on the part of senior leadership. This is a very difficult task given the issues I discussed in the two paragraphs above; however, it isn't impossible. There's also the "tradition" factor. Some processes or actions have become Army tradition. Tradition takes on an almost religious aura in the Army. "241 years of tradition unhampered by progress" is a joke, but has a grain of truth. Traditions shape the way Soldiers and civilians do things and the way they establish and maintain relationships, professional and personal. Because of their near-sacred quality, traditions are very difficult to change or abolish. Most Senior Offices won't mess with a tradition unless it's clearly become injurious to the Service. Example: read RP posts on the Navy's attempt to change the enlisted rates and ranks system in 2016. Tradition won!

I guess ultimately the question is what should be changed?

I'll start, I don't like the black beret. It's wool, it's disrespectful to the Rangers & Airborne (in my opinion), it's Wool, the Garrison Cap was easier to clean (never wore one but I've been told), and it's Wool. I say we go back to the Garrison Cap, it was cloth and easier to maintain.

What's next?
SMA Dailey already covered black socks, rolled up sleeves, and headphones.

I'll go again, the ACU-OCP should have a third pen pocket like the ACU-UCP had. Also we should strengthen the shoulder zipper pockets, I've met two guys who broke theirs already.

AR Policy on wearing the Fleece Cap? It's 32 degree's right? I do believe the local commander has authority on altering that as need be (correct me if I'm wrong). It was 48 on a Field Drill I did and we were allowed to wear them, order was if you're cold don't be cold layer up.
- Side note, found out humvee's suck to sleep in and don't keep the cold out on that drill.

Tradition is peer pressure from dead people.

Talking in a general broad brush does not allow one to address which regulations, customs or courtesies might be able to use some updates. Change for the sake of change is not a good idea. Need to address specifics.
I have seen it from both sides (E- to E-4 & O-1 to O6) and some things I did not understand in the begining I had a better understanding towards the end of my career.

I dont see where any of our customs and courtesies are outdated or ridiculous. Its called heritage and tradition, not to mention respect. Regulations, pamphlets, policy, etc all change frequently based upon doctrine and operating environment.

Get rid of all that bs.

Specialist, you can pray to God that these customs and courtesies, of which you speak, get changed. Just remember, sometimes (like in this case) the answer is "no."