Well that's not what the former ECB chairman Mario Draghi thought about it. According to him they were a success .. See e.g. http://www.ekathimerini.com/245837/article/ekathimerini/busi...

But even mr. Draghi might agree that right now the ECB is pretty powerless, given that it's rates are already below zero.

That's because it's not a monetary policy problem, but a fiscal policy problem.

If you insist in fixing your home with your car jack, don't complain about the results.

Worthwhile read:

https://www.business-standard.com/article/finance/can-banks-...

When we design policy around increasing the value of the stock market, we effectively give stock-holders power. Good policy should create efficient markets, not "high value" ones.