Do you wonder if the fabricated metal ring that the Imperial Sequoia bowls sat in prevented these things from happening?
Holy Grail: 1960s Glen Blue 22 aka The Imperial.
I think the ring helped... but I think it goes beyond materials and construction.
The sequoia is 30+ years old.
Charcoal as a fuel has actually been significantly improved in the last 30 years.
It burns hotter and longer, and our cooking methods have adapted along with it.
I don't think a NOS sequoia would survive more than 3 years of use in my backyard. (i'd love to test this)
@zavod44 built one of the most epic grill tables around. It had gaps and ceramic and it was a SWEET TABLE - but it still turned to charcoal over time.