alt Hacker NewsThe problem is for most practical uses where you need fast calculations the 64 bit precision is enough. For example there is hardly any physical calculation that would need more precision. 64 bit float can be used to measure the Earth-Sun distance to 30 micrometre precision. 128 bits does not just add anything generally useful. For monetary calculations you should be using decimals instead of binary anyway.
Doubles are precise to 1E-16, and the most precisely known fundamental constants have uncertainties on the 1E-12 level. This does not give a comfortable headroom, so the CODATA adjustment that determines the constants from measurements uses quadruple-precision numbers in FORTRAN.