In real life of course this is b*ll*cks.
In real life the wind changes direction "a bit" and changes speed "a bit".
Plus, you know what the wind is at 2000' because you looked up the forecast before you took off, didn't you.
So in reality you're working the calculation the other way, from the pretty good forecast to work out what it's going to be on the ground, to decide whether and how to land.
If conditions are that marginal that you need a more accurate estimate than the above then you're maybe cutting it too fine - you may not wish to attempt to land there, you may prefer to divert to somewhere with one or more of:
(a) someone on the ground with a radio who will tell you what the surface wind is (and remember you can ask for it any time, you don't need to wait for them to tell you after you've called "final", for example on approaching an airfield you can ask for the surface wind in order to help decide which runway to ask for)
(b) a longer runway
(c) a runway more into wind.