That would really depend on how the web hosting provider that provides the VPS's has things setup and you would have to further define "a lot of resources" for that to be a valid point.

We host some pretty active VPS's and have for some time. They've never had an issue with resources and they continue to speak highly of our service. Most of them are on 512MB and 768MB VPS's as well, so it really depends on configuration.

You can optimize a VPS just as you can optimize a Dedicated Server. How well it's optimized will depend on how well it will perform.