Multiple Reasons:
Like most jobs, you have several motives to work there. money, insurance, experience, promotions, etc. Cyber criminals see this as a job, and with this job come multiple motives. These motives can range with the target they intend to exploit, but I have never seen someone put time and effort into a single job without multiple motives.
Money:
In today’s world, everything is increasing in price. Whether it be essential goods, real estate, entertainment, or even investments, the price of absolutely everything has gone through the roof. That being said, there are a range of cyber crimes that can be monetized. Whether it be exploiting individuals with phishing, or deploying an all-out ransomware attack, you have ways to capitalize on cybercrime.
Political:
Living in the political climate the world is currently in, hacktivism is a large component in cybercrime. The political motivation differs based on the person/organization responsible for the attack, but the result is the same. They look to target based on their moral conscience with regard to their political beliefs. This can be companies and government agencies that conduct mass surveillance, social media companies that push propaganda, hate groups, or even individuals.
Recognition:
Being the best in one’s field is a constant push for many industries (auto manufacturing, social media, etc.). That being said, you see hacking organizations push themselves further and further to reach their goals. But many want the credit that comes from being so good at what you do. Not only that, but it could land you jobs within the black hat community. This could allow you to join an organization, or even get jobs from criminal syndicates.
Revenge:
There are many cases in which people can get revenge through cybercrime. This can leave an endless list of targets, whether it be those you know or prominent figures such as celebrities and CEOs. This can range from simply gaining access to someone’s accounts to revenge pornography. That said, it has a broad audience that has grown throughout the years.
Entertainment:
Finding new ways to exploit a target or just test yourself is entertaining. Whether it be manipulating an API to get privileged access to information not found on a webpage, hacking your neighbors Wi-Fi or simply hacking a friends Facebook account, these are crimes (no matter how entertaining it may be).
Boredom:
Finally, I do believe boredom is the least motivating factor when it comes to cybercrime. This is not to say that it cannot lead to extensive crime, because many cases (such as cyber bullying and grooming) have grown over the years. I am saying the motive itself is not strictly boredom. Sadly, individuals take pleasure in these areas. It is not only because they are bored, but they also have other underlying motives for these actions.