Planned obsolescence people. They want you to buy a new car every 3 years. If they genuinely wanted you to keep the car for life, there would be service schedules on cam follower and cam chain. The only reason there is one on the cambelt is they are liable if it snaps.....within the warranty period only, naturally!
Ever wondered why there is a magnet in the gearbox to attract swarf, but not a magnetic sump bolt? Because with a plain sump bolt you can't see just how much debris these engines kick out!
Things are different in the markets they care about, mind. America for example, get a 100K powertrain warranties, and the cam follower was recently added to that, or extended to 120K iirc. What do we get? 2 or 3 year powertrain warranty?!
Keeping this cars going indefinitely is a nice little middle finger back at them...... so long as you can afford the parts.