Pretty much all bikes and most newer cars have that problem. They are designed to be disposable. The manufacturer will only support them for 10 years, then the parts supply starts to dry up in a hurry. Pre emissions American cars, air cooled VWs, vintage British bikes, Harleys, and Vespas are some of the very few older vehicles you can still get parts for, because there is a market for them. Most of these vehicles have a cult following. A lot of mechanical parts will likely be available for the XT225 for quite some time, but they are cheap, poor quality chinese stuff. You can get a new top end or carburetor for under $100 now.

The above is my opinion. Your mileage may vary.
1994/2001 custom built XT225 with a ton of aftermarket parts.