There's only 15-20% IPC increase from Ivy Bridge (which a 2012 Macbook Pro would've used) to Skylake, there's a similar increase once again to Ice Lake but the clock has actually dropped from 2.5 to 2.0 at least on the 13" side (at least that's what everymac tells me). It is only the core count that shows an increase and their use case might not be more than two cores.