I´m pretty sure they have been made by experienced professionals that have the time, money, patience, and *mental panache* to finish "big" 3d projects. Hence, soft is unimportant, MONEY is important, assuming you are experienced and 3d is your second home.
If you have money, you don´t need to earn anything right now to pay your bills, and you can focus on just working into the dark with the well known mantra "it´s done when it´s done". Kapish?
All the best selling assets are most probably done by artists who are "baked" by investors or have a good financial standing. Without money, good luck with creating "best selling" contents!