The biggest issue is zoning laws created decades ago to keep the suburbs segregated by limiting multi-family housing. Zoning being under local control means those who already own property in all these towns to have all the power to approve or prevent new housing, particularly multi-family housing. And the expense of building here means developers are mostly building huge, luxury houses because they can't make a profit off building starter homes on the limited real estate available. We've taken some baby steps with the law requiring suburbs to zone for multi-family housing near commuter rail stops, but the NIMBY pushback has been fierce. (Weston in particular has been going apeshit.). What we need is for the state to take more control of zoning away from localities. What Gov. Newsom has been doing in CA to tackle the same problem recently is probably a good example to look to.

Things like rent control and affordable housing lotteries are red herrings. The only thing that's going to fix the problem is increasing the supply...by a lot.