Socialism will fail because people are more than happy with the system we have which means that it will never even be attempted in the first place. Comfort of capitalism creates complanency. We simply don't need socialism so urionrically one might say there is no DEMAND for socialism in the MARKETPLACE OF IDEAS. Here are a list of reasons why:
1) Abudance. Capitalism creates an immense amount of abudance that can be felt throughout society no matter what class you are, what race you are, what gender you are, etc.. Look around you even the people who work at McDonalds or Walmart have cars, computers, shelter, access to the internet, access to education, food, etc. these would be considered luxuries only fit for the most elite of elite 1,000 years ago, yet everyone has access to these basic products and services. I've never met a single person who hasn't been able to afford a phone for example, even with NEET bux one can buy a cheap chink phone for like $50. Hell somebody living on food stamps are living like kings and don't even know it. It's all about perspective. I seen so many people in the lower class eating McDonalds and other fast food for example which would be considered luxuries in the third world or 1,000 years ago.
The reason why there is abudance is because there are so many different price ranges to choose from. For example if you're poor you can buy a car worth 2k instead of 25k. If you're poor instead of buying a $200 shirt you can buy a $1 shirt. It's still a shirt. It's just not as luxurious. Just a testmane to how many options you have in our system.
So in terms of basic needs being met. Capitalism proves that AND more, no matter who you are. Whether you are living on welfare or working minimum wage. Most people look at luxuruies and assume that just because poor people can't afford them it means the system is shitty. Not true. Luxuries are really illusions anyway. People are manipulated by companies to spend so much on expensive goods.
2) Class mobility. In capitalism, if you are smart and hard working you can be poor as fuck and still end up middle class or even part of the elite class after you die. It's not impossible. In fact the transition from lower class to middle class is very easy if you think about it. All it takes is getting good grades, getting into a good degree (hopefully paid for by scholarships if you did well) and finally getting a job in a field that is in high demand in a growth industry. STEM is one example of a pathway that can propel you to the middle class very easily, unfortunately most leftists are attracted towards the humanities which don't pay very well. So if you're smart you will always make it. In fact it's impossible not to make it because if you can provide SKILLS and SERVICES that people want, then people would WILLINGLY pay you for them, it's simply impossible not to succeed if you do have these things. I would say based on this, that capitalism is mostly a meritocracy [not taking into account inheritance and all that stuff, I think that's irrelevant here]. The people at the top are mostly the best of society in terms of intelligence, creativity, looks, personalities, etc.
3) Freedom. Capitalism is the best driver of individual freedom in the world. In capitalism you have the freedom to live anywhere you want, work any job you want, buy anything you want, be anything you want and do anything you want provided it is within the means of the law. This personal freedom cannot be seen under any other system. Under communism you will be a slave to the state (see USSR and Mao's China) and they will tell you where to work, how much you earn and where you will live. This is slavery. In capitalism there is so much freedom that some might say there is too much of it. Also capitalism is tied to democracy aka the best system of government where the people decide who leads them and the direction they want the country to go in.
In short, I can probably write a whole book on the benefits of capitlaism but I won't. I have a lot on my plate right now in terms of engineering school work, my side-business and my social life so I can't write anymore. But yer this is a good primer on the benefits of capitlaism hopefully to enlighten/educate.