The carpet in my parents home is from 1969... and it looks like new... no kidding, they are very careful with their wall to wall carpet
I've had carpet in rentals replaced after one year... absolutely destroyed... cigarette burns and soda stains...
I remember when 100% wool carpet was sold as lasting a lifetime... it was very expensive and I know some of my parents friends still have theirs...
It all comes down to care... and to a lesser degree, quality and type.
If you want new carpet and willing to move and put back the furniture... have a talk with the owner... I usually change out the carpet for long term tenants around year 12 upon request... don't want to loose a good tenant over some carpet.