In short
The devil possessed people to oppose Christ’s work, but as Jesus consistently was able to drive them out, Satan stopped using demon possession to try to hinder the Saviour’s ministry.
Demon possession was particularly common during the days when Jesus ministered in Palestine. This is because Satan purposefully attempted to oppose the work of Christ by using these demon-possessed people. Every time one of them crossed Jesus’ path, the question arose whether the Saviour would be powerful enough to defeat this evil spirit. Time and again he drives them out, so much so that towards the end of Jesus’ ministry, the devil ceased to employ this strategy.1
24 So his fame spread throughout all Syria, and they brought him all the sick, those afflicted with various diseases and pains, those oppressed by demons, epileptics, and paralytics, and he healed them.