Sony WM-10 Walkman Commercial

I have been obsessed with this commercial for the Sony WM-10 Walkman for years, because it's not only well-made (treating the "crafting" of the Walkman like a piece of fine art) but also because my mind was BLOWN that a Walkman could be the same size as a cassette case.

What they do NOT tell you in this commercial is:

1) the Walkman would have to expand (with part of it sliding open) whenever a tape was actually inserted (as seen in the pic above)
2) to make it so compact, they had to engineer a very small motor as well as a flexible voltage converter (so only one AA battery would be needed) -- both parts that would be fragile and damage-prone
3) it was and is hideously expensive

In the years since this commercial aired, I've also noticed that it is a 25-second ad, with 5 seconds at the end for the sweepstakes info. I wonder if there's actually 30-second version out there (most TV ads back then ran for 15, 30 or 60-seconds).  In addition, why did they add a Dolby circuit (which increased cost and weight, and took up space) to what needed to remain a fairly compact package?

Click here for info on the other Walkmen in this compact "family."  Like the ads in this post, this aired in September, 1983, during Saturday Night Live on WKYC-TV.