That being said, two points :
1. I trade. So basically wether it is a bubble or not, I don't really care. I go day by day. You probably know the sentence "markets can be wrong longer that you are solvable". It is important that you know your timeframe. If trading, then whether there is a bubble or not is not really important. The actual drivers of the market are. And btw, one of the "why" of the great momentum to the upside this past month has been the positioning and too many people speaking about the crisis...
2. Speaking about a longer term view, the skew is to the downside. It is not so obvious as you are mentioning though. The CBs are increasing their balance sheet a HUGE amount. And the "don't fight the Fed" has been seen so far. I would have a tendency to think that we may see a lower low before seeing a new bull market, but the CBs are not helping this view. Probably we need to see a new theme as a new wide spread second wave.
You should think in term of probabilities better than having this kind of strong opinions that is necessarily wrong as you are speaking about the future and you don't know 100% sure the outcome.