Rimworld definitely makes it harder when you're doing well. You can control the parameters a bit though in the storyteller settings. It depends on your colony's wealth, number of people, how long it's been since something 'bad' happens (colonist dies or gets injured), etc.
This is advice I've given to new Rimworld players, and I hope it was helpful. The game (on most difficulties) is itching to give you the next "scenario."
Building your wealth in valuable equipment is not very good at the start of the game, because your town's silver value will go up much faster than its defensive/offensive capabilities. You end up putting a target on your back for raids.
Better to build a surrounding wall and set up trap corridors than to worry about getting everyone a gun.
I've had success doing that too. Buttload of traps. The raids that will circumvent your traps are definitely a problem though. Also the raids that just have a bunch of grenadiers can destroy your defenses in no time.