though, replacement of T-18 rakes into shatabdi wud b in public interest.
but
lets look d other side as well i.e financial/economic/business aspect
JAT Raj covers d distance in 8:20 hr whereas VB covers d same distance in 6:38hr.
....
more...
or better example wud b comparing NDLS LJN shat and BSB VB b/w NDLS-CNB
LJN shat covers in 5:10hr while VB covers in 4:08hr. 1hr is saved.
.
so IR deserves to charge more (may b only a bit) to earn a operational profit.
.
moreover T-18 rakes gave birth to new category of trains i.e. Vande Bharat.
.
OR
SHATs are replaced VBs altogether with increased fare. same dat happened in d case of Raj - Tejas Raj.