Harder to change doesn't make it more or less correct, just means wrong information sticks around longer. Because revision history is kept and changes are instant, it's easy to fix bad changes. For topics that see extensive astroturfing, they can be restricted.

It’s worth remembering that the entire point of a wiki is that it’s quick and easy to make a change (the name means “quick” in Hawaiian). Being quick and easy to change was the defining quality of Wikipedia and its advantage over more rigid traditional encyclopaedias. These days editing Wikipedia seems like you have to fight bureaucracy and rules lawyering, and doesn’t seem very wiki-like at all.