Hi ...
I think what you're saying is correct in case of other compound subjects as mentioned below. Here is some explanation from
Magoosh. Please correct me if i have misunderstood anything from it:
Additive phrasesThere are many constructions that have a meaning similar to P and Q, but achieve this in the form [single noun] + [phrase]. For example,
a) P, as well as Q,
b) P, including Q,
c) P, in addition to Q,
In all of these, the phrase that follows P is called an additive phrase. An additive phrase is not part of the subject, but is simply a separate noun modifier modifying the subject. In all three of these, P alone is the subject, and if P is singular, the verb is singular.
Compound subjects: The OR ruleThe rule for OR is a little trickier. These three constructions all follow the same rule for the OR pattern:
a) P or Q
b) either P or Q
c) neither P nor Q
What matters is only the number of the last term of the sequence. If there are two terms, then only the second term matters: if the second term is singular, the subject takes a singular verb; if the second term is plural, the subject takes a plural verb. Whether the first term is singular or plural doesn’t matter at all. Thus:
5) Either the President or the three senators are going to speak ….
6) Either the three senators or the President is going to speak …
7) Neither the CEO nor the members of the Board are responsible for …
8) Neither the members of the Board nor the CEO is responsible for …
All that matters is the number of the term closest to the verb: the number of the verb follows the number of this nearest term.
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I completely agree to your point but my point here is additive phrase should always be preceded as well as followed by a comma. This isn't the case in the given sentence. So, I considered it similar to either X or Y.
I wonder what would be the real construction for such cases as I haven't encountered any such example before.