In retrospect, I think Crenshaw may have been hurt by the video music revolution as much as any artist -- he released a couple of performance videos in 1982, but "Whenever ..." was his first 'real' video. My guess is that he wasn't into the whole music video thing at the time. Additionally, his 60's influenced pop songs may have been seen as a bit dated in the early 1980s. Looking back on them now, however, reinforces the timeless nature of his songs.
"Whenever You're On My Mind" is a great example of his work. On its surface, it is a love song, but the catchy hook and thoughtful lyrics make it one of the better love songs written in the decade. Plus, you have to love a songwriter who uses the word reverie (go ahead, you can look it up if you like ... I'll wait). Amazingly, neither the song, nor the album (Field Day) even charted upon their release in 1983.
The video was played a little back in the day, and then seems to have been forgotten. In fact, it was hard to find even today. For folks who like it, I suggest listening to samples from his first two albums -- there are a lot of pop classics there.