You can't really have a long career AFTER not releasing much but you could have a long career during which you release little and sporadically, although it's uncommon.
Sometimes a one hit wonder will be remembered decades later because of their hit being played but their career will not be continuing in any really sense so this doesn't count.
Strictly speaking this thread relates to artists who over an ongoing period have released songs only very occasionally. This is uncommon within major label music - the labels want to make money and you will usually be contracted for a specific number of releases over a given period. You are signed to create product. If you don't sell, you'll be dropped.
Someone like Kate Bush has released far too much in my opinion to be considered for this - and too regularly - more a case of going on a lengthy hiatus a couple of times. A solo artist (like KB) has an advantage here as they can't split up.

Sade Adu has done this also and the rest of the band have worked as Sweetback in the interim. Blondie were prolific but split and returned about a decade-and-a-half later. If you split up and reform you have not necessarily had a music career in the gap years.
It's more likely within mainstream music that an artist will disappear, making an unexpected reappearance much later, than to issue recordings very sparsely over a period of time.
I'm not sure if people will come up with too many examples that strictly meet the criteria. Kele Le Roc was dropped with indecent haste but has continued to sing on various artists' records and on her own, on a variety of labels since she ceased to be a chart artist. I'd say she would qualify (especially since she has never released an album beyond her major label debut) but she has a few too many releases to have had a truly sparse career.