The other problem often overlooked about people testing systems for bear markets is that liquidity often disappears also. Markets generally tend to have a naturally bullish bias and as a result when things turn south the money goes elsewhere just as quickly as the volatility and the share price. There isn't much point taking a large short position if you're unable to close it due to a lack of depth.
Personally, I enjoy keeping myself busy during the day doing non-stock related stuff... occassionally a bit of company research. I generally try to keep all my trading decisions to outside of market hours though to stop over trading. As for making a living from it, trading is simply a means to an end. The gains from trading usually get siphoned out into another investment once they are sizable enough (e.g., property) to provide a little diversification across asset classes and a little more spice in my life and things to do
I wouldn't give everything else up unless I'd met all of the following conditions:
- Had paid off all outstanding non-productive debt (credit card, car, boat, etc.)
- Had at least 12 months worth of repayments for other debt in "the buffer" (own home, investment properties, etc.)
- Enough to cover all reasonable additional expenses in "the buffer" for the next 12 months (insurance, rent, energy, etc.)
Add +20% to the required "buffer" figure. If you can set that amount aside and not touch it and your trading continues to be successful enough to live off, then I would let it be a consideration. Rental income and dividends would get added to the buffer. Living expenses get drawn out. At the end of the next year give myself a pay rise and then the same formula would apply.
If my trading capital is the same or less than what it was at the start of the previous year, then it is either time to reduce my living expenses or re-assess how viable the decision to not work is. As I believe Techa already pointed out, it is about aiming for excess. If I was trading and just making ends meet I wouldn't be comfortable giving up everything else.
And there is a lot to be said for the social aspect of working in a business. It also helps that almost all of those around me are quite active investors in one or more asset class and a wealth of information in their respective areas