This may be a slightly different angle, but in my experience, real estate pros are far below average when it comes to retirement asset protection. In 2008-2012, I was representing real estate pros who had net worth on paper of $10M, $20M, even $100+M shortly prior to retaining me. They were meeting with me to see if they could save their homes, along with other assets.
While amassing assets, they had failed to put any of those assets into retirement vehicles or accounts of any type. Usually those types of assets are protected from the claims of creditors. Their real estate, which is where they had virtually all their equity, is not exempt from such claims in most states.
As a result, these professional people, (who were clearly sophisticated investors and business people), faced near total loss of their assets when the real estate market dropped. They were worse off than someone working for a smaller paycheck, but who had at least had a small IRA or 401(k) plan.
With a little bit of asset protection planning while they had the net worth and ability to move assets, these real estate pros could all have ridden through the recession with millions in exempt protected assets.
I hope this gives you a perspective about the worst case scenarios. See an attorney today if you need help with asset protection.