I somewhat live this lifestyle right now, with mountain biking, not climbing. I've sacrificed a "good, stable" job for one that allows me to ride, train and race 7 days a week if I desire. I work in the bike world, and I work around people who are 40-50+ years old, with no retirement, who have been dirt bagging it since the beginning. I'm 27, and I know my time in this world is coming to an end. I don't want to be 40-50, still working in a shop because I have to. Now, if that's what you want to do after FI, great! But to know that I'll be working till 70+ is not something I want to become a reality. I have co-workers in their late 50s, who still spend the summer making money, just so they can take 3 months off in the winter, and then return to the shop completely broke to work again all summer.
With that being said, it's really hard to consider the sacrifices of getting a "real" job, one that means I may have to dial the training back, race a little less, come into work on time no matter what, even if I need to get a 4 hour ride in. But, what I've learned is that while money does not provide happiness, it provides stability. And when I feel stable, and secure, I enjoy riding, training and racing even more. I still would never change the years of my 20s that I've spent doing whatever I wanted...it's the best! But I have become much more frugal in the past year, and making changes in my life to move towards a more financially stable existence, while still maintaining a focus on my outdoor pursuits. I think it's a balance. One that I haven't personally been ready to even think about until about a year ago.
All of that being said, I think you've got a great idea, but you're preaching to a tough group of people. I'm the only person I know in my mtb world who even gives a thought to financial stability, and the climbing world is even more dirtbag than the mountain bike world.