Many companies outsource their services to small companies or individual resources. and keep the profits.
Some are good, but most are not that good.
Answer to your question:
About lead generation, there are some common things
1. BD reaching to prospects
2. Communities
3. Advertising
4. Backlinks from blogs and newsletters
5. Social Media, etc.
But most of the time, the websites are not that effective in converting the visitors into an actual customers. We have worked on this in the last two years. Now we have a better way.