Hi Juraj,
It's cool that you ask this question, I am glad you asked. It's a complicated question...But, Kahein can answer why specifically he or her is looking for a freelancer. But i honestly think It's a matter of choice and how you want to pilot your project (the architect's firm). He clearly stated that they are not looking for a cheapo, and that the price is set by the visualizer if the direction likes their work. negotiating price and timelines is plainly business 101, I don't know what the right answer is. I guess I saw this from the get-go, that's why I said its a healthy approach to take. I believe they want direct contact with the person creating the visuals or the art so to speak, to achieve the look they are looking for.
Second part of the question I think deals with how to run a viz business, if your reading this and you are visualizer looking to make easy money, get out now and go into real state or banking. Visualization like architecture is a tough business, it requires hard work and a lot of personal effort. I would to have my own studio one day. I see my first challenge to be, finding the right people with the same drive I have. And I wouldn't like to run a studio like a talking head and closing business deals. I would like to sit along side my team and do the actual work with them (leadership by example). I also believe that giving employees freedom on managing the project economically and qualitywise, makes them feel it's their project and not the company's. If you give employees ownership of the project, they will create great work. But I cant assure this a good business strategy, I have yet to learn. Sadly I've never been given this opportunity in my firms I worked for (but I give them my best). Currently I am an intrapreneur, I would like to switch to be an entrepreneur and have the opportunity of putting a price on my own work. In an ideal world that's a beautiful thing to have, it must be very fulfilling. In the future would like to manage a business on the premise that every one in the chain can profit for the companies work. For the time being I flying solo, and I can guarantee the work I have on my page, because I did it alone.
All in all, there are different ways on managing a visualization, and its matter of how you decide to carry on with it. There are no right answers, this is just my personal belief and business ideals.
I asked Kahein to kindly consider me, I understand that my colleagues here have great work with their own stylized methodologies, and this is healthy in a job market. Thank you for reading.