Sorry to hear of continuing problems with your new gun. The relatively common reports of new S&W guns with problems, and the factory's apparent inability to adequately repair them is rather disappointing.
To me at least, the "cant get parts for the older ones" foreboding seems much less an issue than "cant get a reliable/workable gun or repairs from the factory" issue. Single or numerous trips back may eventually get one going, but Im not sure Id have patience for it. Parts for older ones are not an issue from my experience, they just dont necessarily come from the factory, such as aftermarket hands and cylinder locking bolts, or at least factory parts are not in a new package. Im glad Im able to do some of the work to keep one running. It was all fairly intimidating in the past, but curiosity got the better of me and started tinkering and learning.