Learn English – Meaning of “since changed”

According to Wikipedia

six ways from Sunday

(idiomatic, colloquial) thoroughly, completely, in every way imaginable  

Other answers have done a good job of outlining how "jealousy/jealous" may be distinguished in meaning from "envy/envious." Therefore, I'll focus mainly on the specific question "Has the meaning of jealousy changed in current usage?"

No.

The meaning of jealousy/jealous has overlapped with that of envy/envious for a very long time; this use (or "misuse," depending on your opinion) of the word greatly predates the 1980s. (On the other hand, it's possible there have been shifts recently in the frequency of use of one versus the other.)

In the Oxford English Dictionary, this falls under definition 4b of jealousy, and there is a list of early examples of the word being used this way:

4. The state of mind arising from the suspicion, apprehension, or knowledge of rivalry:
   [...]
   b. in respect of success or advantage: Fear of losing some good through the rivalry of another; resentment or ill-will towards another on account of advantage or superiority, possible or actual, on his part; envy, grudge. [bolding added]
   • [...]
   • 1650 R. Stapleton tr. F. Strada De Bello Belgico vi. 21 Lest this warrelike Preparation might beget a Ielousy in the minds of princes, his Majesty satisfied them by his Ambassadours.
   • a1715 Bp. G. Burnet Hist. Own Time (1724) I. 208 This drew a jealousy on me from the Bishops.
   • 1836 W. Irving Astoria I. 90 There were feuds between the partners themselves, occasioned..by jealousy of rank.

And here is the relevant definition (with historical examples) of jealous from the OED:

4. Troubled by the belief, suspicion, or fear that the good which one desires to gain or keep for oneself has been or may be diverted to another; resentful towards another on account of known or suspected rivalry:
   [...]
   b. in respect of success or advantage: Apprehensive of losing some desired benefit through the rivalry of another; feeling ill-will towards another on account of some advantage or superiority which he possesses or may possess; grudging, envious. [bolding added] Const. of (the person, or the advantage).
   • [...]
   • 1477 Caxton tr. R. Le Fèvre Hist. Jason (1913) 42 Alle were Ialouse of him, But Iason neuer thought on none of them.

The meaning of the word has certainly evolved over time, but this particular evolution occurred centuries ago. I'd also like to note that the same ambiguity appears to apply to the related word in modern French, jalousie, as defined by the Centre National de Ressources Textuelles et Lexicales:

3. 1501 jalousie « envie, dépit que l'on éprouve à l'égard de ce qu'un autre obtient ou possède » (Chastel de joyeuse destinee ds Jardin de plaisance, XLV).

Whether one should use the words "jealousy" or "jealous" with this meaning is a separate question; but I hope I've shown clearly that they not only are, but they have been for quite some time.