Agreed, and from what we have gleaned over the years and from feedback from Independents the issue is more to do with the pistons, among other things being different to the previous 276hp engines and in particular that the pistons were of a different construction and tolerance.
But undoubtedly the high oil consumption issue is also down to how the car has been driven and how well it is maintained - bear in mind the oil level is notoriously difficult to read on all the pre HR 350 engines, and not least what petrol has been used with knowing that ragging the engines over 5k rpm using less than 98RON fuel ain't good news. Yes owners like us on here who take a pride in looking after their cars will make the effort, but sadly not everyone does (whatever the car they drive).
The other factor we have picked up on is that GT4 296bhp rev-up engines do not seem to have suffered the same level of oil consumption issues and although there were limited numbers, the fact they were assembled prior to the introduction of the rev-up engine suggests they continued using the original DE pistons, or at least the construction/tolerance were the same (better?)