Let's do some hard cold arithmetic here.
In all honesty, it will take 20,000 rounds to kill it, that is over 8000 dollars worth of ammo.
Unless you are super active that shoot 1000 rounds a month ( that is shooting every weekend every month), it is not something to worry. But if you shoot that much, you probably are into competition and most likely you will use an AR instead of handicapping yourself with a TAVOR. Most people shoot 1000 to 3000 rounds a year....and most people probably will want a new toy in 5 years anyways.
Most people who bought extra barrels will just end up having the barrels sitting there for a couple years and collecting dust.