Socialism in its true form is economically sound as it is the distribution of a nation's wealth equally among its citizens. Socialism recognizes the importance of each person's contribution to society without putting certain tasks before others. It makes sense because why should a lawyer or doctor be held in higher regard than the person that makes the road or car that allows them to get to work or builds the house or grows the food they need to survive. Unfortuantely socialism has never been properly executed because some people are greedy by nature, and leaders in so-called socialst countries have created dictatorships instead of properly following socialist principles.
No, socialism does not provide the right economic incentives, because it allows a person to get paid, whether or not they are productive, and whether or not they produce anything of value. A person should have to contribute something before they are compensated. Socialism does not provide an incentive to work hard, and this is reflected in the output of these countries.