It's not a fear - it's a reality. If people get less benefit from working, they will be less likely to work. Less work means a less productive country and more freeloaders.
Scientifically proven to be wrong. The reason is that people get bored by stuff and hate to be told to do something, while they love to achieve something. You can see this when people play video games and invest a lot of time and money into this. You can see this in open source projects, etc. Besides that work (or achieving something) is a good way to impress. That's also why people who don't work, even if they have enough money are more likely to become depressed and commit suicide.
https://www.youtube.com/watch?v=u6XAPnuFjJcI am still not a socialist, not an American and don't think they are doing it better than socialists. I think they do it worse. The US has an awesome concept, because it's based on liberty/freedom, but sadly the people are being manipulated all the time. In a way the US are way more authoritarian, than China for example. However, the way this is enforced is completely different. Advertisement, religion, nationalism and the resulting society enforce a much stricter rule set than it would be possible doing top-down using a form of dictatorship or police state. If you change the society to enforce things on their own then you also prevent movements to change the status quo. If it's not just the government, than it's way harder to declare an enemy. In the US corporations are very strong, so power is spread. This may be the cause for the stability of the US. Don't get me wrong, I am not saying this is planned, it's more like the evolution of a society. Maybe it's even beneficial that this attitude causes hate by other and an enemy people like terrorism is good for nationalism. I guess there even is a demand for this. People in the US appear to need some kind of enemy and some strong men to face it. This enemy also justifies stuff like COINTELPRO, the PATRIOT act, even if they are meed public by the freedom of information act. It appealingly works pretty well and countries like China are trying to copy this strategy. Btw. in China you have one party, while in the US you have two, but in most areas they aren't too different from each other. It's the same in most Europe countries. They usually are like extreme centrists reflecting the intersection of everyone's thought and since people are not smart in every area, just in their own ones the outcome is pretty plain and often simply dumb. In China you have the big cities, that are a lot like the US, while the rural areas are more like the medieval and people don't care for them, because they don't know about it. In the US they are more like "everyone can achieve anything", so it's pretty much their fault. It's the problem if -some- (really, just some) libertarians and liberals, who think people would be equal and therefor it's everyone's business to care for themselves. I actually know that most libertarians and liberals think there should be institutions caring for people, but things shouldn't be enforced and it should be an institution, not the government. The thing is that such a society wouldn't really be too different from a socialist one. With that I mean that both systems would theoretically work well, if people would be informed or better inform themselves and actually care. I think most people mix up political or economical systems with society. A society defines how things are, not a small group of rulers. Of course, a small group may influence society, but pretty much everyone may do so, else we would still have kings ruling everywhere and not what people call democracies.
tl;dr: Forget socialism, capitalism, liberalism, anarchism, nationalism or whatever -isms. It just prevents people from working together and doing the right thing.
Want a proof this works? See Bitcoin. All kinds of people (whatever -ism they are) are here, because it's awesome and probably the right thing. It's the same for the internet and same for pretty much everything else. Just because things work, not because they are liberal or conservative.