I think there's a lot of variables that need to move in a specific direction to line up a significant down turn. Specifically, layoffs would need to happen, maybe the stock market tanks at least 20%, or interest rates a lot higher. The San Jose job market is still strong with a lot of building in downtown SJ or north SJ/Milpitas too so hard for me to predict if its q416 or q218 the downturn starts and when does it end?
Even in the worst case scenario around 2006 the peak San Jose median price was $700k bottom of $500k in 2012 and now at $800k (according to Zillow). If I were to time the market and wait 6 years from top to bottom, my rent expense might have been 2k x 12 months x 6 years = $144k.
I feel the rent I'd pay per month is essentially a down turn (in my net worth) and buying a place and having a tenant pay would be an upturn. A 30 yr fixed 3.5% at 20% down on a 600k purchase is $2,900 principal and interest and 700 tax and insurance so thats not far off from 3k rent and maybe a tenant pays $1,500?...Just giving you a different perspective.