>So millions of native speakers are in error,
You can bet your fanny they are.
including authors of
>style guides and the like.
Yup, thats really funny. A good one.
From one of those style guides (UNLIKE CALD) still worth paying attention to:
But there is one corrupt and meaningless form, apparently gaining ground, that calls for protest. When a clause begins with as if, it must be remembered that there is an ellipse.
"I treat her as tenderly as if she were my daughter" would be in full
"I treat her as tenderly as I should if she were, &c."
If this is forgotten, there is danger in some sentences, though not in this one, of using a present indicative in the place where the verb were stands. So:
We will not appear like fools in this matter, and as if we have no authority over our own daughter.—Richardson.
This may be accounted for, but not justified, as an attempt to express what should be merely implied, our actual possession of authority.
As if the fruit or the flower not only depends on a root as one of the conditions among others of its development, but is itself actually the root.—Morley.
This is absolutely indefensible so far as is is concerned; depends has the same motive as have in the Richardson.
But this looks as if he has included the original 30,000 men.—Times.
There have been rumours lately, as if the present state of the nation may seem to this species of agitators a favourable period for recommencing their intrigues.—Scott.
This is a place where as if should not have been used at all. If it is used, the verb should be seemed, not may seem, the full form being as there would be (rumours). Read suggesting that for as if, and seems for may seem.
General Linevitch reports that the army is concentrating as if it intends to make a stand.—Times.
A mixture between it apparently intends and as if it intended.
As if the same end may not, and must not, be compassed, according to its circumstances, by a great diversity of ways.—Burke.
May should be might. As if it may not is made to do the work of as if it might not, as of course it may.
The same rule applies to "as though."
http://www.bartleby.com/116/215.html
(some quotatio nmarks added)
That's what separates the sheep from the goats.