You've got it backwards I'm happy to say!
.. Now I'm not saying that at some point in the distant future domains won't be come obsolete .. but the truth is ...
Domains ARE the phone numbers (still very much a must 100 years later)
Google IS the phone book (no longer relevant today)
It might not seem like it .. but Google is in serious (long-term) trouble in terms of pure search. Live, auto-complete, auto-prediction interfaces will indeed take a huge bite out of search page results (their bread and butter for displaying ads).
But below all the search .. regardless of how people search and get their results .. those actual results still need addresses. Particularly when it comes to businesses. Obviously some types of data do not
need an actual domain and could simply reside on IP addresses .. but there are a lot of reasons why domains will still be relevant .. mainly in terms of sales .. and trust/security.
Most importantly .. communication is still absolutely vital today and will be for quite some time. Email is here to stay for a very long time. In fact .. if anything is to ever replace phone numbers it will be you email address(es).
There was a short time when big corps could have started the slow process of usurping the need for domains (namely FACEBOOK) .. a few years ago quite a few startups launched only on Facebook and other social media. But with Facebook getting too greedy and placing too many barriers (and money) between their corporate users (pages/groups) and the users/fans of those businesses .. many businesses have now woken up to the fact they absolutely
NEED their
OWN online presence and address .. and cannot place the fate of their business in the hands of some communications giant.
Domains aren't going anywhere anytime soon. That being said .. how they are used could and likely will change quite a bit as interfaces change. Alexa, Siri, Google and the sort will certainly bring huge changes to how we connect with information and data .. but that information still needs to be found somewhere.
All that being said .. there certainly are possible changes that could affect value of domains. In the future these kinds of interfaces could diminish the importance of having a .com vs a ngTLD for example. But that's a different story ...