What for ? 8 p cores is more than enought for a ST applications an E cores are more effective.
Let's use math. 12900k uses 303w for just 8 p cores. Let's assume, that it ll scale perfectly so 12p cores ll use 450w
that's insane.
With E cores enabled it uses 297w and performance is 37% faster in cinabench and 2.5% slower in gaming
So with + 8 E cores u get other 40% for 50w maybe ? For 4p cores u ll get 50% for 150w
Note: only if it scales perfectly. With +150w heat there is no way, that it ll boost as fast as 8p
So that's why Intel goes for more E cores. They have no room for more p cores in power budget