Rent control is causing a shortage of suitable living areas and property owners are ignoring maintenance costs.
"Well then, let's pass another law!"
Property owners are passing rent controlled properties to their friends and family, or influencing local government regulations to do complicated rezoning laws or even straight up bribing inspectors
"hmmm, well let's just pass more laws then!"
How many times are you willing to try a solution that continues to fail before you give up? It would be funny except in the mean time your belief that a couple "smart people(TM)" passing laws is ruining the lives of the very people you profess to want to help.
EDIT: The fact you believe it is perfectly reasonable for landlords to be held hostage and forced to do 'buy outs' of tenants who refuse to leave an apartment that isn't theirs is all I need to know about your thug mentality.
If rent control were actually causing a shortage, we'd expect that rents would have continued to rise during that time. Instead, the far more likely conclusion, given the data, is that rents are being driven mostly by increases in demand.
It is difficult for the armchair libertarian economists of HN to accept that, while rent control probably puts some upward pressure on rents (in theory, anyway), that effect is likely totally swamped by the demand-side imbalance.
An enforcement in issue. In NYC the laws are actually aggressively pro-tenant on the issue of deliberate neglect; if you don't keep the basic services working (or keep the building reasonably free of infestations, for example), the tenant can use that to delay any attempted eviction processes (justified or otherwise) quite substantially. The smarter landlords in NYC all know this, and hence generally resort to buy-outs as a tool for vacating tenants. Overt harassment-by-neglect does happen, but is quite rare.
It also reduces tenant mobility.
To some extent, it reduces mobility within the local market (and this effect can be quite significant, in some markets). But in an unregulated environment, a great many of these people simply would not be able to continue renting in the local market, at all. So it's a tradeoff, basically.
Rent control also directly causes Ellis Act evictions, IMO.
A non-sequitur; there's no reason one needs to have something like the Ellis Act in order to have rent control. NYC's market (famously) does not, for example; and profit-driven conversions of the sort you mention are generally illegal, and easily blocked in landlord-tenant court.
In other words, the Ellis Act causes Ellis Act evictions; not "rent control."