Keep some salt handy.
Vast majority of political pressure to restrict the housing supply comes from your average homeowner. They have been taught, and incentivized, to treat their home as an investment vehicle. Building more housing generally lowers their home's value due to supply vs demand.
Rent can be affordable, or housing can be a 'good' investment. We can't really have both, but it's a lot more palatable to blame the problem on Blackrock or rich condo owners than your audience.
I'm sorry, but affordable (and newly built) housing, at least in Central Europe, where I live, is most certainly a thing. It's a question of building type, unit size, density, local infrastructure, government subsidies and the location overall. I can recommend taking a look at the housing market in cities such as Vienna. Newly built housing can be affordable and of a high quality.
Why that is a seeming impossibility in the US, I cannot say, though I have seen some, albeit more than likely somewhat biased, evidence that at least some forms of higher density, low-rise mixed-use building styles common in Central Europe are not possible in certain areas of the US due to zoning laws. Unless I am mistaken, I seem to remember that zoning legislation was something the LWT piece on the topic specifically pointed out as one of many parts of what is a multifaceted problem that needs to be approached as such.
Another area that is, according to reporting, very good on the front of providing newly built, affordable housing is Singapore, though I know no first-hand experiences (I have no friends currently residing in Singapore public housing) to truly contextualize whether the system there works as well as it appears to. In either case, though, new housing can be affordable if done right.
> They have been taught, and incentivized [...]
Ok, but if that is the case, then both new and old housing cannot be affordable. You are saying, new housing by definition is not affordable, then point out that, for historic reasons, owners expect their property to increase in value, making old/existing housing even less affordable.