They were certainly in print longer than David Bowie. The first Eurythmics RCA disc was probably Sweet Dreams (Are Made of This), which exists with an RCD prefix. It's probably late 1983 or early 1984, and one of the earliest RCA titles on CD. All of their regular albums from Sweet Dreams to We Too Are One were platinum certified here in the UK, so the only explanation for not seeing their LPs with any regularity in charity shops is the vinyl revival. I haven't checked my local record store for Eurythmics CDs because they charge a ridiculous amount per CD, irrespective of how rare or common it is (good if there is something really rare on the shelves).