Is this where you think you've gotten me in a "gotcha!" moment? Because you haven't. Let's put my comments in context.

ディーブイディ is a spelling of "DVD" as though it were a word. It's a reflection of a mispronunciation or the letter V, and it includes the lengthening of the first "D."

In other words, the letter V was mispronounced as ブイ, and this pronunciation led to the spelling.

V → "bui" pronunciation → ブイ spelling

The actual pronunciation as a result of native Japanese speakers' inability is not at all related to the spelling.

Here, I'm saying that the pronunciation of ヴィ is /vi/ regardless of how Japanese people mispronounce it.

/vi/-sound → Japanese linguists say, "Oh, we don't have a way to spell this new sound." → invention of ヴィ

Then, there's another process that happened:

Japanese people see ヴィ → Japanese people: "WTF is that? How do we say that? Oh, that's a way to spell V? Then we're just going to pronounce it as ブイ because we don't know wtf the difference is." → Japanese linguists: "Ugh"

Your DVD example was describing a process that is completely unrelated. There is absolutely no denying that ヴィ represents /vi/. It can never represent /bui/. That is a mistake.