Well, Apple basically designed Siri and then left it alone for years. Other companies have built off of Apple's early success with Siri and continued development. The problem with Apple is that it needs to realize that it has to continue innovating or lose market share to Google or Amazon.
I also have the Echo and I think that its language comprehension ability is similar to Siri's but it is able to do more things. But it's also very limited because it has to wait for its infrastructure to catch up with it. The Echo isn't meant to be used simply for flash briefings, weather, etc. The long-term idea here is to have it control most aspects of your home (e.g. lights, ceiling fan, thermostat, coffee maker, etc.). And whether that pans out we will see in the next few years - if manufacturers don't end up going in that direction, you just have a beefed up version of Siri. But if they do, now you have an integral piece of home technology that can revolutionize the way you interact with your home.