Many times the Qur'an and sunnah don't go into the details of the wisdoms behind rulings. The Companions weren't faced with detailed intricate challenges to the minutiae of the faith; their focus was on the core things. They didn't have time, to put it bluntly, to do a sociological and anthropological and economic analysis of Islam, and it didn't matter to them. Allah told them to give in zakah and in charity and they did. They accepted it as part of the system that Allah had designed for our world.
Your acquaintance is conflating the modern welfare system and its potential effects with zakah. They are not synonymous. You can see there are three sides to zakah: the giver, the receiver, and impact on the rest of society due to that transaction.
As for the giver, a secular system accords them tax benefits and perhaps a feeling of having done some good. In Islam however, giving zakah has direct spiritual benefits, which one can only appreciate with iman. Giving zakah is a form of purification of one's wealth. It is fulfilling an individual obligation that Allah has placed upon His slaves and therefore carries great reward.
For the receiver (and there are rules on who or what can receive zakah), the immediate and tangible benefits are obvious. It is a means of obtaining food, clothing, and other essentials necessary to live. The point of zakah is to empower the receiver to rise to the level of nisab (amount over which you have to give zakah) so that they in turn can give zakah. The restrictions on who can receive zakah are what make this different from a welfare system (they are not synonymous nor is one a replacement for the other). Historically, this system has not had the kind of impact where people are simply content to receive zakah funds and not work.
Finally, the impact on society of zakah is that it is a tax on the wealth of a person and not their income, and so they are motivated to invest their wealth in business and trade. Zakah pumps money into the economy and cycles it, rather than letting it sit idle and sucking money upward into the pockets of the already wealthy (this is the impact of riba).
Finally, generally speaking, the argument that the very idea of giving in charity is bad because it promotes complacency and laziness is specious and arises from extreme libertarian and/or Ayn Randian philosophy. It is the very epitome of selfishness and arises from a very human-centric worldview. If complacency and laziness are the outcome of charity, the problem is with the administering of the charity (who, how much, what kind, etc.) and not the concept of charity itself.