That's largely a myth told by people with shiny new Coscast engine blocks to sell you.
They run too hot because everyone runs lawnmower-grade 95 octane petrol these days, which contributes more than anything else to liners breaking free especially with the liners being thinner on later (90s onwards) 94mm-piston engines. I do wonder if the switch from thin steel "shim" head gaskets to composite ones allowed the liners to move more?
Anyway they only break liners free completely (the infamous "dropped liner") if you run them absolutely bone dry of water until one piston expands enough to jam in the liner and start hammering it up and down, just before the engine seizes entirely.
It's cheap and easy to get the liners knocked out and the block machined to take "top hat" liners, with a lip around the top that clamps them in place, something like £1800 last time I looked.
