Kyrotech grind is real, but there is a light at the end of the tunnel, because Kyrotech income exceeds the amount required by released characters.
You say 20 new characters a year? That is 1.66 a month, which comes out to about 670 kyros on new characters each month.
Kyro income per month starts with
90 from dailies
160 from ABs
about 80 from TB
About 60-70 from TW?
40 from GCs
So that can be 400 a month without energy or currency. Supplement with kyro purchases with GET and GAC currency, along with energy farming and you can outpace newly introduced units.
Of course, it takes a LONG time to reach that point, especially for growing accounts that dont have all the chase units yet, but there is a (small) light at the end.