Possibly correct, but there are people who've ridden the big KTM twins, big BMWs etc across the Simpson.

It's all to do with confidence. Soft sand is a mongrel, but ok if you keep the momentum up.

For the record, the Simpson crossing involves struggling across 1100 sandhills, some fairly piddly but most are a bit of a challenge on a heavy bike. Momentum is your first best friend, followed by fresh jocks. Lots of punters fall off at least once. Errrrm... One of my mates slipped off just over the crown of a dune, I came whistling over the top, couldn't stop and ran over both his wheels. Poo flew out of both of us.

I'd do it on a well set up Tenere, but never on a stock one. I'm not good enough. Wider tyres, run fairly soft, as light a load as sensibly possible and common sense. Don't do it summer imo.