Why America Will Be "White" Forever

It's common to see predictions like the U.S. will become majority minority 30 years or so from now, just as California and Texas as majority minority now.  I've no problem with these predictions, or with the reality when it arrives (I'll be scattered molecules by then), but I want to note that the validity of the prediction depends on the definition of "minority" not changing between now and 2050.

But definitions of ethnicity and race are socially constructed.  Just ran across an interesting proof of this:
 This BBC News site is on the gender pay gap in the UK.  But what interests me are the ethnic breakdowns (because the gap varies by ethnicity):

• White Irish
• White Other
• White British
• Black Caribbean
• Black African
• Indian
• Chinese 
• Pakistan/Bangladeshi

To me it's a reminder that ethnicity/race is socially constructed.  Note that there are three "races" represented--Caucasian, Asian, Blacks, but that's imposing American categories as of 2017.  There's no discussion of the categorization, and I'm making the possibly wrong assumption that the UK often uses these categories.  Apparently for the UK the differences among the ethnicities are big enough to force race into the background. I'm certainly aware that the Brits were more prejudiced against the Irish than the U.S.  And because the U.S. has more immigrants from different countries (i.e., Vietnam, Philippines, South Korea) we don't usually divide Asians by country or religion (i.e. the Pakistan/Bangladeshi versus Indian and Chinese distinction.)

What I predict will happen over the next 30 years is this: the definition of "white" will change so that it includes the majority of Americans, regardless of their heritage.

•  In part this will reflect the confusion caused by intermarriage.  In the Washington Post magazine an Indian-American woman writes: "But in 2017 America, my particular jambalaya of “features” frequently has me mistaken for Ethiopian. Trinidadian. Colombian. African American. It depends on which city I’m in, what I am wearing and, more often than not, who is doing the asking."  That's an example.
• In part this will reflect the logic of discrimination--what is the purpose of a "minority"?It's to define the majority, meaning that a "majority-minority" nation loses the inestimable virtues of being discriminatory, of defining the "other".  So the solution will be either to shift the definition of "white" so it includes the majority (you can see that in attempts to define Obama as not really black) or to bring to the fore another term which applies to most Americans. I can't think of one now, which is why my bet is on "white".

This is what we've done before, successively redefining "us" to include more than Anglo-Saxons, more than Brits, adding Germans, Eastern Europeans, Southern Europeans, etc.