Some websites have 1000s of pages. It takes me about 20 minutes to write a page with a bunch of keywords and no real thought ie) its not very good. Can somebody tell me how a website could have 1000s of pages. Are there some sort of automatic content generators. Do people have databases that are counted as pages?

Yes to everything.

Usually sites with 1,000's of pages are ecommerce sites that sell thousands of products. And these pages are created by pulling info from a database.

There are content generation programs out there too. These generate spam pages.

Making a page just for the sake of including keywords isn't a good practice. After discovering what keyword phrases people are using to search for your prodicts/services use them naturally in your page copy for the benefit of your end users..