Screw it, I've had a couple to drink so I'll give my ill-conceived two cents.
The ability to retain capital, in this case equity through real estate, generates barriers to others as real estate is generally stable as an investment and there exists only a finite amount of real estate. As this occurs over time, equity becomes continuously consolidated, whether it be through individual landlords acquiring more property, or grouping of asset class owners through real estate investment trusts (REITs). When a sufficient share of a geographically local area becomes owned by a select number of holders/entities/persons, there are not many mechanisms that can drive the price to rent down for regular consumers to adequately "shop around" for the best deals (thus working against the idea of "free market" principles). As a result, few people can build enough wealth to crystalize that cash into equity, resulting in an ever concentrating wealth in those that already own real estate.
Property ownership itself is not necessarily a great investment in all cases, and thus should not be considered a de facto negative, as there are several risks that are taken on by the landlord in terms of maintaining the value of the property. While it is true that property generally increases in value over time, figures do not typically account for the cost associated with maintenance and reoccurring costs (i.e. taxes, local fees), which can result in several cases being effectively neutral to negative from an investment perspective--this is especially true when looking at alternative uses of capital investment.
This is important because the landlord has taken the financial risk associated with costs that are not limited to merely rent, along with potential risk exposure to increases in holding costs, such as a newly instituted property tax.
I say this as someone who owns a property elsewhere, but currently lives in a rental property.
The difficult part with "getting rid of landlords" (or however you might choose to phrase it) is the process to do so necessarily requires the dissolution of most basic tenets of the right to contract, and the right to property in general, both of which are foundational to western commercial enterprise. The other challenge here is that the western "capitalist" model has had the opportunity to actually be tested, documented and grown upon, which allows for more targeted criticisms, while the untested socialist model does not carry the historic look-back to afford the same mental digestion.