I had the exact same experience when a plumber replaced our hot water heater because most manufacturers in the 1990's were using a internal plastic dip tube made by one company that used a defective plastic that disintegrated into small pieces that clogged the faucet screens.The last time I had to replace my hot water heater I went scrounging around on the Internet and discovered that the reason they die is because of galvanic action that causes the fittings to corrode. Hot water heaters have a "sacrificial anode" that's designed to be the target of this action - it corrodes first before anything else does, but when the rod is "used up" then the rest of the tank starts to go.
Now here's the interesting bit - Hot water heaters are sold with 6, 9, or 12 year warranties. The only real difference between them is how long or how many of these anode rods are installed. It's a perfect example of planned obsolescence.....
When I asked the plumber how long, in his experience, a 12-year heater would last, without hesitation, he replied, "Twelve years."
I told him my parents had a water heater with a copper tank that was more than 60 years old.
His reply: "Yeah, well they learned not to do that anymore!"