Most of the time, people who end up with these kind of problems (and stretched timing chains/worn plastic guides) are not the original owner, and have no idea about the previous maintenance history.
Timing belts were a great idea in the past when most 4-cylinder engines were SOHC and non-interference. Once you add in high-tech features such as VVT, and eliminate internal clearances, the use of a timing belt ceases to be a good idea.