How does an E6 have 6 service stripes?

Maybe this E-6 has a medical Profile that exempts him from being discharged from the military that he received during combat duty. I don't know the in's and out's of how the Military operates these days since I've been retired over 20 plus years.

All you can say is that he retired as an E6. There are many reasons for this. He served many combat deployments, so the most likely reason is that he was in an MOS with slow promotions. I had many assignments where I served in positions above my pay grade, had many awards (MSM being the highest), always met or exceeded the requirements listed for E7. Never made the E7 list. How do you know that he is not on the promotion list? Don't be too quick to judge based solely on rank.

Well it's like this, I Retired in 1989 with 20+ years as a SSG E-6 I have 6 service strips!! I did my time in Vietnam Germany and the USA so SUCK IT UP and DRIVE ON!!!

Could’ve had a break in service , or transferred branches. Happens all the time.

I was an E-5 with 8 hash marks, I liked where I was at in rank, I was following my dad's thought, why be greed and you don't need the headaches, he was a Master Mason, and didn't want to over extend himself.

Could be several things. When I made my E-5, I only needed 500 points. My other, more difficult to learn MOS required 998 points. So, it could be that. Also, I served in the 1980s. We had a number of Vietnam era helicopter pilots that were RIFed down to enlisted crew chiefs. They mostly stayed in for retirement. The most medals that I ever saw on a uniform was one of these guys. He was only missing the US Congressional Medal of Honor, but he did have the Vietnamese one

Having served 30 years, 10 active and the rest in the guard, all of the E7 slots in my unit were slotted for AGR soldiers. Unless you where full time you didn’t get promoted. I understood this was the deal and served proudly through multiple combat deployments.

Any number of factors could be at play for not being above a certain pay grade with that many years of service . Doesn’t make the man any less of being a good soldier . OK ......

He could be National Guard. Often times National guard soldiers have difficulties getting promotions as they rely on open slots -- I've seen it...

Many ideas. You just have to be open to the possibilities and opportunities the Army provides. I retired an E6 after 20. USANG for the first seven years being slotted in an E4 position for my last half of service there, without worrying about advancement. I got back in and started development courses and promotions in the reserves, then active duty in leadership positions. When I wanted to continue with my 7 there was a long promotion halt in my MOS. Things happen and just continue to do your duties.