The real reason why people hate the fact that things change rapidly and previously working "methods" now become useless is just because of ONE reason:
You are doing internet marketing as your MAIN BUSINESS. Internet marketing per say can never be your business. Internet marketing is just a method of getting users through different virtual channels.
Every bsuiness that is successful and having SOME sort of longevity is having a CORE and MAIN PRODUCT, and then - based on that, the layers of marketing will come into play.
That means: When you have a product - a GOOD one that actually solves something or provides value in any way or form - and do the marketing, then your product will be your business and your BRANDING will be your worth.
Even if some SEO shit happens to you, you still got the branding. You still got users and you still will get users through their users etc. Sometimes even things like explosive growth a la twitter, facebook, etc. happens.
Think about it guys,