"Capitalism failing a majority" isn't "capitalism is failing".
The former statement is always true, because capitalism serves the winners which will always be a minority or move to become a minority if it isn't (how it got in that state is anyone's guess). The question is only how much it's failing the majority. The two's interests can align for a time, but the needs and wants of one are almost always in direct conflict with the other's. The failures currently are massive, thus why running on helping people and actually doing the job of government (its role in a so-called "mixed-economy") is working better than anti-socialist/communist rhetoric to combat it.
Soundbites are good, but so is replying to what the other person said(mostly so we don't put words in other people's mouths)