With the average shelf life of the reel is 3 years, parts are available for 5 years after the reels discontinued, that means the parts is actually available for 8 years, and no matter you buy a $50 reel or $800 reel, they all only come with 1 year warranty, so they didn't make customer think the expensive reel will last any longer. The average life of the reel is 5 years, if someone only fish 5-6 times a year and he owns a Stradic, the reel will properly last 30 years, on the other hand, someone fish 200 days a year, the same Stradic may only last 3 years, think about this way, if I spent $200 on a Stradic and I fish 30 days a year, after 5 years is 150 days of fishing, it equal to $1.33 per fishing day which cost less than a doz of worm.
Now look at the production side, When manufacture create the tooling to make a reel, they make a percentage of extra parts for repair service, once these parts run out, you are out of luck. The tooling do not last forever, after the production is finish, the tooling may be worn and will not cut the part properly, to make new tooling will cost hundreds of thousand dollars, not economically just to try to keep a $3.00 parts in-stock. The money will be use to make new tooling for new reel, which will fill the demands of consumer who always wants to have the newest, most advance design and cutting edge products.
There is no money to only manufacture parts for repair for non-current product, not in the reel business or any other business, manufacture or any aftermarket company. Here is how most reel repair shop work, someone bring in a old reel for repair, parts no longer available, the customer feels there is no need to keep the reel, they left it at the repair shop, now, suddenly, some of the parts from this reel become available to the next customer who happens looking for the parts, you never know, may be 2 months down the road and you go back to Shimano, they may have the parts just because someone drop off some old reels there.
Shimano service is very good, as long as they have the parts; they will fix the reel for you no matter how old the reel is, with a small charge which is understandable. There are lots of other reel companys out there selling high end reel with no parts available at all, they only give replacement reel within the 1 year warranty, you get a NEW REEL if it broke within the first year, after 1 year, no more service.