Hill was more valuable than all 4 of those guys combined. Still won a SB.
Chiefs churn good O-linemen each year. They picked up Jawaan Taylor,--a 25 yo solid pass blocker with all 66 starts in his first 4 years. For the money, Brown wasn't worth keeping.
Clark is a solid loss, but the D still has Jones, Bolton (2nd in solo tackles last season) and added Drue Tranquill.
Can't say they haven't added or replaced...