Is this subjunctive?
The following is a part of a Lucy Kellaway's column in FT.com.
Why do estate agents still exist? Travel agents are gone — or going. Estate agents, who were hated long before Tim Berners-Lee gave up train spotting to invent the world wide web, were always going to be the first to go, come the internet age. Instead the reverse is happening: as I cycled through Islington on my way home the other day I counted 17 estate agent shop windows in one street.
I suppose the essence of the sentence including the phrase come the internet age is
Estate agents were always going to be the first to go, come the internet age.
Then, what is the grammatical role of the phrase "come the internet age" in the sentence? Is "come" subjunctive? If so, what is the meaning?
Solution 1:
Origin
Historically speaking, yes: come is in origin a 3sg (third person singular) subjunctive form of the verb to come in this context. This particular usage is not old enough to go back to Old English (where the subjunctive was quite clearly distinguished and separate from the indicative), but it does go back to Middle English, where the subjunctive was partly distinct.
In the four or five Middle English examples quoted by the OED article on come (senses 35 for the ‘come what may’ type and 36 for the ‘come spring’ type), the form is always spelt come, which can only be a 1sg present indicative, a singular present subjunctive, or an imperative. The now identical-sounding infinitive and the past participle were still mostly written comen at the time. The 1sg indicative can be ruled out easily; a 3sg subjunctive is more likely, though theoretically I suppose an imperative is also possible (acting here as a 3sg imperative although English imperatives usually apply only to 2sg and 2pl, the 3sg and 3pl imperatives being historically expressed by the corresponding subjunctive forms).
In addition, the definitions of these two senses themselves are short blurbs that specifically call them presents:
35. come (present) is used in such phrases as ‘come what may, or will’ [compare French vienne que vienne, Italian venga che venga, German es komme was da will!] , ‘come weal, come woe’. Also in ‘come what might, or would’, where the sense is past.
36. come (present) is used with a future date following as subject, as in French dix-huit ans vienne la Saint-Martin,—viennent les Pâques, ‘eighteen years old come Martinmas,—come Easter’; i.e. let Easter come, when Easter shall come.
The comparisons to French, Italian, and German subjunctives parallels the origin of the expression in English.
Current use
In Modern English, on the other hand, it is doubtful whether this is really a subjunctive anymore, especially in sense 36. In 35, there is arguably still a good deal of verbal meaning left: the structure in come what may can be extended to other verbs (“cost what it may”, etc.), so I’d say it’s quite reasonable to label this a verbal form still; clearly a subjunctive one.
But in sense 36, which is more exactly the one asked about in this question, it is doubftul how much verbal meaning is really retained—I would say not much. The pattern can certainly not be extended to other verbs (“eighteen years old be Easter”?!?).
Some dictionaries [Collins/19] do still list this as subjunctive; but for this usage, I would side with those dictionaries [ODO, Wiktionary] which list it rather as a preposition which is more or less synonymous with by. Though definitely nonstandard, I have occasionally heard people who so clearly thought of this come as a preposition separating it from its object (historically its subject) that they were able to naturally produce structures like “What time will she be here come?” [= By what time will she be here?].
Solution 2:
This "come" is a past participle and used mostly with a date after it as a when-indication. Examples
1 How old are you my pretty maid? -- She answered me right cheerfully, I'm seventeen come Sunday. Remark: I would prefer a comma before "come Sunday", which means when Sunday has come.
2 Come spring, there will be plenty of colour in the garden. Longman DCE Meaning: when spring has come/will come.
"Come the internet age" meaning as/because the internet age has come.
Now I really searched around a bit more to see how "come Sunday" and similar dates in the sense of "starting Sunday/from Sunday onwards" are seen or explained. Most natives on forums see it as subjunctive, but it is clear that those views have no weight as they confuse optative and concessive subjunctives without any distinction.
Even renowned dictionaries as Collins have no qualms to declare it as subjunctive.
I had to do a long search till I found one web side where "come" was seen as a past participle. A very long thread and views are diverging.
http://alt.usage.english.narkive.com/bZwYIqnD/come-time
Result of my research: There is a great number of views that take "come Sunday" for a subjunctive. But there are also views which favour past participle and even derivation from a Latin ablativus absolutus. My view, whatever it is worth: I think a subjunctive is improbable and I favour derivation from a past participle.
Edit: MacMillan labels "come+time" as preposiion. OALD as well: prep, old-fashioned, informal. - Of course, it is possible to see "come+time" as preposition. But it gives no understanding as to how the verb to come develops a preposition. I prefer to understand language. "come+time" is a case similar to "time+ago". It is better to know how things develop than to simply learn, "ago" is a kind of preposition and it is in post-position.