I believe SEO is not dead. or rather SEO is just a guideline to helping you get a better rank.
SEO tools should just be there to remind you of usage of keywords as those are what people search for in search engine.
content you write and back links helps to bring in more traffic and as you said google "steal" information hence they know what people actually want.
Think logically, google change algorithm just to suit customers (us/advertisers) and prevent sites that provides useless information from getting better rank.
they keep changing because black hats keep trying to break the system.
End of the day, if what what your site has is good (content and seo wise) you will still keep the rank while the algorithm change.