It has always been the case that people working within a field over-estimate how long it will take to achieve things within that field. They are hyper focused on their tiny part and miss the big picture.

To make accurate predictions you need to use data, trendlines and growth curves. It literally doesn't matter how many "experts" are surveyed, the facts remain the facts.

A few people making data and trendline based predictions hold far more weight than an infinite number of "experts" that base their predictions on anything other than trendlines.