It's alleged or implied that this highly experienced pilot entered a manoeuvre at the wrong speed and wrong altitude. Both readings are affected by the static. But due to the accident damage they couldn't check the static; only the instruments were tested. The instruments are useless if the static isn't OK. I was an instrumentation and control engineer in an allied field so my comment isn't a wild guess or stab in the dark.
Whilst a blocked static would freeze the altimeter, the ASI would continue to function 'normally' apart from a tiny error associated with any changes in height from the equivalent frozen static pressure. If the static source had failed at ground level (it clearly hadn't) then the ASI would slightly under-read at 3000ft.