Remember, Musk is all about scalable manufacturing and products. If this was other's tech from 20 years ago, where's the massive commercialization? They failed. Musk is focused on this aspect, and he will (given his past achievements) succeed.
Here is a video from 2014 of someone controlling a quadcopter with their mind with zero implanted electrodes: https://www.youtube.com/watch?v=lsraC04Mm8w
Having 10x more electrodes that stay active for a long time, attached to self powered unit under skin with low latency wireless comm link is a major step forward.
Besides that, why the pushback? Is it coming from field experts who are like, "bah, old hat as shiny new. humbug!"; disappointed futurists who expected more ("we were promised flying cars and intelligent robotic spouses, and all we got was 2000 electrodes in our brains, and 140 characters"); misMuskists; people who sense unfairness in praises lauded upon this, in their mind, mediocre achievement, echoing to them a theme that the already-anointed and, in their view, undeserving, accrue all praise, while the genuinely meritful, themselves, for example, are overlooked, yet again?