I guess it's a fair assumption you never once attempted to calculate your own taxes in the first decade of filing taxes? Did you just drop some papers off to an accountant the first year that you reached adulthood?
I've used an accountant occasionally, but only when I had genuinely confusing tax issues involving international work or work across many states where I wasn't sure whether there existed a "nexus" that required me to pay taxes in State A or State B. Even then I did my best to double-check their work, and often caught errors/omissions. Most of my friends also do their own taxes (and have since 2006), regardless if they were line cooks or painters or engineers or MBB consultants. So I'm just not familiar with the lifestyles that lead to this.
I'd actually understand it more for people who've entered the workforce since 2005, because TurboTax/etc became much more popular. I did taxes with my dad in the mid-90's before most homes had internet, and back then it seemed far more likely that people would understand how taxes worked, because there wasn't super-easy software to do it for you.