Close but no cigar.
The problem was not just the design of the system, but also (and perhaps to a far greater degree) the very poor workmanship. When they opened-up the joints, the architects and engineers found that instead of being tightly grouted they were filled with any old crap including pieces of newspaper. In the absence of mechanical ties or anchors, this led to an inherrent weakness.
The other issue, however, was a realisation that - even if built properly - the partial collapse of part of the structure could cause a pancake or cascade effect and lead to dispropportionate failure.
This in turn led to the removal of gas from the affected properties, although it continued to be used in other high-rise properties of the period.
As an aside, architects and engineers study this - usually around first year at university. I therefore find it rather amusing that Truthers, for all their professed knowledge, barely know of it. Very peculiar indeed.