After an invention is patented, can't similar inventions be patented?

After an invention is patented, similar inventions can still be applied for as long as they are novel and creative.

Most people who buy patents are fraudulent companies that are nominally "technology patent consulting companies". Some companies tell the patentee that they have the intention to transfer, specifically defrauding the patentee of the so-called service fee, and few companies really want to accept the patent. No enterprise is willing to buy patents that are easy to imitate and have little technical content.