There are countless other scenarios that could have seen this lead to a gear up landing.
As I said in my post, the crew only made 1, repeat 1, mistake.
If you as a member of the aviation community really believe that 1 simple memory based mistake makes for "countless" opportunities for an accident then you display your ignorance of the defences put in place. Push your industrial barrow elsewhere.
We can play scenarios all you like, but the fact is that there is not a shred of evidence that more then one layer of the numerous defences was breached in this event.
Like it or not, single defence layers are broken during probably every single flight, maybe not all as exciting as this one, but all capable of "theoretically" bringing down an aircraft if another X number of problems arise.