Vanguard is really good at listening to feedback and using that to inform fixes to the various web and mobile applications. So if you're using the UI and see a survey, you should absolutely submit this feedback. They listen to it, and effect that change quite quickly on modernized pages.
There has been an immense push to modernize the Vanguard site and the underlying architecture. This has been an enormous effort over multiple years. Since Vanguard was always a "no-branches" company, it's always been web-based. So, as a result, much of the site was built at the "bleeding edge of the time" but they are now in a position where that needs to be fully modernized.
Vanguard's architecture is enormous, but they are getting closer and closer to fully modernizing the site and retiring legacy completely. Its something that has been happening and will continue to happen over the next few years.
From my experience actually yes many are if you are a paid subscriber. Free services certainly have slow or non-existent support models. But IMO a service owned by a multi-billion dollar company should at least be responding to their support tickets from paid users within 5 business days.
Curious what the use cases for iOS 10 are? This isn't a criticism of your comment but more just wanting to learn why a user might still be using iOS 10?