Domaining isn't a easy job and it takes effort to find end users who will buy your domain, although this also depends on the quality of the domain in question.
The only complexity there is - is the amount of work you have to put in. You either monetize your domains successfully through parking or development and passively wait for a buyer to approach you or you take active action to get your domain(s) noticed and accomplish a sale through hard work.
Remember, renewal time is only a year away and you need to have funds to back this up.
If you have a substantial amount of domains this could be a problem if you haven't made enough via parking or development.
And if you can't fund the renewals by other means such as your regular day job then you would be disapointed in yourself you didn't try hard enough to make a couple of sales to fund your upcoming renewals and even have something on the side for development (To create a additional income stream) or to use in your regular life.
You just can't spam millions of people with your domain for sale email if you think that would be less complex?
It's a numbers game and perhaps in the first year you would not sell your domain(s) but maybe the following year you will.
Patience and hard work are key elements in domaining.
I'm not a pro or experienced domainer but these are elements which the pro and hardcore experienced domainers would surely agree with me that are necessary to be active in the domaining business.
That's something you have to accept and is part of the job
