This debate has been raging forever and I have seen all sides of the argument now. I'm still with SEO being a broad field that encompasses all digital optimisation, but where do you sit? I found this article this morning, have a read and decide where you stand.
I have said this before, but, you see, search engines like Google are always going forward for content and quality, not backward for malicious people trying to actively game their system. The way they have found to be vital parts to determining whether a website is incredible with a lot of effort put into it and distinguish that from those that contain only rehashed information is by letting people other than the webmaster tell them. This means through backlinks, which has been the hallmark of this since Google's inception, and now social media, because, obviously, if other people enjoy a webmaster's content, eventually someone will link back to them or, to now give some power to the majority of the internet, allow them to share it on their social circles. Obviously, there are people who can still purchase bot likes and followers to increase their page ranks, but I'm 110% certain that Google is aware of this and is already on a fix.
Furthermore, Google's updates to its algorithms these past months should be a clear sign that SEO in terms of adequately telling the system what the webpage is about, following their best practices, and creating original content should prove by now that SEO is not dead, nor will it ever be. The only SEO that will die out is blackhat SEO.