There is a pretty big gap between “it might crash so I have a backup” and “it has never worked so let’s fake it”.

not from a customers perspective

Not equivalent though, by a stretch.

That would be 'Tesla making a video of a working vehicle and showing it at Conf because they are not sure it will start!'

There are reasonable expectations of 'show', but showing something that literally does not work, as 'working' would be fraud.

The equivalent would be 'there is no software' so 'just make a video fabrication of software' and then show that at the conf.

No, it's the equivalent of taking some designer's mock and presenting it as a real website, without having an actual client or backend or anything else in place (which companies also do all the time).

Hardly. This is more like faking your website demo because you don't know how to use the internet.

> because you aren’t sure it’s gonna work on stage

Because you aren't sure it's going to work at all, ever.