On the second point, the correlations between hyped startups and established software vendors often isn't that strong. It doesn't necessarily need a major crash for markets to decide that Uber actually isn't worth 40% of the current global taxi market.
Indeed in some cases there's the distinct possibility the correlation goes the other was and profitable public incumbent tech providers will benefit from the loss-making VC-funded upstart unicorns in their market crashing and burning
When folks talk about the desire to bet against the private IPO bubble, they're thinking about a broad, significant decline that affects lots of companies, not the downfall of a specific company. Realistically, this type of broad, significant decline is unlikely to happen without a major correction in the public markets.
So long as the public markets are seen as being strong and stable, it's unlikely that the small, relatively illiquid market for private tech companies will correct itself.
Indeed in some cases there's the distinct possibility the correlation goes the other was and profitable public incumbent tech providers will benefit from the loss-making VC-funded upstart unicorns in their market crashing and burning