While some of this may be threatened by proposed legislation at the moment, especially for IRAs, self-directed investors have generally had the ability to invest into any asset class except collectibles. 

I believe the biggest issue many landlords currently face is the over supply of new housing that was rushed to the market due to a number of factors including the changing  tax abatement legislation and favorable financing terms that were available when these properties were first purchased.

Who the hell knows what COVID legislation will continue to get passed that hurts landlords.

On a side note, these are the kinds of misinformed statements/questions/bullet points  that lead to bad legislation and  higher rental costs. 

This article is about the legislative history that lead to the creation of MERS and why.

Sorry, but your rent just went up $200/month due to new legislation.

If this is in other countries, I guess Government will roll out new legislations to ban this kind of thing in a lighting speed. 

Both are still possible, but the legislation has recently changed so you just want to make sure to stay on top of it. 

You're one act of legislation away from losing your business model in an Air BnB.

Throw in city/ jurisdictional specific factors like major employers and legislation affecting them etc and you’ve got your system.