Flight Data Recorders

I was reading this article about a Russian air crash - here is an excerpt...

Russian investigators have discovered that the cockpit-voice
recorder from the crashed Itek Air Boeing 737-200 contains no
trace of the ill-fated jet's final flight.

...

MAK adds that the quality of the flight-data recorder information
is "unsatisfactory" because of partial thermal damage to its
magnetic tape, caused by the intense fire which followed the crash.

Which made me think: magnetic tape?! Surely we've come far enough that
we can be using solid-state storage in flight data recorders?

Does anyone know why FDRs would still be using what, to me, is archaic
technology?