Nuclear plants are rather trickier than some industries to redevelop (the fuel casks are stuck in regulatory limbo, the rest of the plant is just a massive structure, much of it radioactive enough to reduce the otherwise significant scrap value and require special procedures, built durable enough that it'll be expensive to demolish) which increases the odds that Maine Yankee HQ will do their best to classify the site as some sort of minimally-operational status in perpetuity, because hiring a couple of guards to wander around and punch the clock is cheaper than fully pulling out, leaving the town with a big derelict structure.
They are hardly alone in that, though. All kinds of industrial processes (especially anything inherited from the good old days when Men Were Men, Cigarettes were a health food, and PCBs were a Miracle of Science), even if their buildings are cheaper to tear down, leave the underlying site in lousy enough shape that it's usually cheaper just to say 'eh, fuck 'em' and choose a greenfield location somewhere else. Even something as minor as a gas station can be Wacky Remediation Fun Time if their storage tank leaked before they went under or moved.
(The only other aspect, though the article is polite, or feckless, enough to ignore it, is that nuclear plants operate under an NRC license, which is of limited duration unless renewed, which requires a variety of testing steps, so their demise is probably rather more predictable than the usual '$FOOCORP moves to China to save 10 cents per widget' story. If your town is basically fucked without its resident nuclear reactor, you really want your town leadership to be well informed(or doing their best to batter down the doors and demand to be made aware) of exactly where in the lifecycle the reactor is, whether HQ is looking for a renewal, whether there are issues that would scuttle that, etc. Predicting a 'Haha, Outsourcing Surprise!' event is relatively challenging. Predicting whether or not a reactor will get recertified or mothballed may not be trivial; but it's a much better defined problem. My guess is that there's a really ugly backstory there. Either the town ignoring the problem to bask in the present, the operator stonewalling/flimflamming the town until it was time to give them the shaft, some of both, some other flavor I'm not thinking of; but that would be the one major wrinkle distinguishing a reactor from any other 'industrial site not easy to remediate'.)