“If the vapor pressure build-up causes the gas tanks to crack, rather than the spider webs to blow out....it seems the problem is weak, cheap gas tanks!”
Things were at one time WAY overdesigned. This cost money and weight. Whereas 40 years ago a part might be 300% stronger than it needed to be, now it might be 110%. This could not be done without computers and simulations.
Transmissions are a good example in a car. You could probably put 800 horsepower, no problemo, through a Turbo-Hydramatic transmission of the 60’s and 70’s with maybe a tweek here and there. BUT...that transmission also cost almost 20HP just to operate!
Worse: BUILDINGS were way over-designed because there was no way to simulate stress, so people used the seat of their pants and multiplied by some number. The Empire State building is WAY over-designed. Modern skyscrapers...not so much.
You’re right.
And most tanks now are plastic (elastomers, actually)
Which is not all bad.
I’ve had several steel tanks on old cars rust through underneath the straps.