word on the street - AWD Auto has verified it by tearing down a block - Subaru has started installing the better headgasket MLS design during a certain year...i forget when, like 2010 or 2012....i'd get one that has that new headgasket design.
with timing belt and headgasket done that car is good for another 100,000 miles, why not run it? how much do you want for the car?
I still own my 2001 Outback LTD and have loved it although it has had too many (4) brake jobs, 2 timing belts, complete exhaust system at 70K including Y pipe and catalytic converters and recently had the head gasket replaced after 114K miles and religious oil changes.
We are due for a new car and I still lean toward the Outback but my husband is turned off by the costly repairs
from this little bit of information the problem is most definitely not the vehicle. it's improperly maintained (not by you - don't take offense). the mechanics are likely not very good, not trustworthy, or simply too busy to give subaru or vehicle specific repair advice or cost effective quality advice. something inefficient is happening.
"Subaru's" do not need 4 brake jobs....well unless you're driving hard or tons of city driving, towing, mountains or something. Basic facts are that Subaru braking systems are actually quite robust and will not cost any more to maintain than anything else. You are completely at the whims of:
A. your own knowledge
B. your mechanic/dealer - they often aren't a good source of low cost maintenance
if you get a nissan, subaru, or chevy - you'll always have terrible repair costs if you are totally reliant on a mechanic...unless they are exceptionally good at quality and being cost effective (extremely rare) and know that particular manufacturer very well.
my best advice - is to use a forum like this to help you with maintenance costs if you want high mileage out of your Subaru. we can help you with proper, inexpensive, and the best course of action for brake maintenance. forums like this (USMB is also a really good one for highly technical Subaru related information) have more combined experience than any dealer/shop in the country - use it. we know the best way to approach every maintenance/repair from a quality, reliability, and cost perspective. mechanics usually can't specialize like forums can.
a Subaru catalytic converter of your age should have never had the catalytic converter replaced - they are robust, expensive, and last the life of the vehicle. in the event that you, like me, live in rust prone areas saw a broken rusted flange - it simply needs welded back in place - they tend to break in one spot. replacement is ridiculous when welding takes 20 minutes and 50 cents of welding materials.
everything you listed sounds questionable - like i would have been able to approach all of that with less expensive and better options that would have resulted in fewer total brake jobs. you weren't getting the best possible maintenance service.
your year Outback (2000 - 2002) was eligible for a 100,000 mile extended headgasket warranty campaign by Subaru - so if it would have happened a few thousand and years earlier it would have been nice. sometimes a call from subaru gets you reimbursement or aid in some sort even after the fact - might be worth a call, particualrly if you're int he market for another Subaru.