The super capacitor ended with the Sian, it's been stated in numerous articles and Reggiani made it clear the tech can't be implemented for mass production cars.
And we can't compare the V10 and V12. The V12 is the heart and soul of Lamborghini which is why the Lambo suits had to fight the VW board to keep it alive. The V10 on the other hand can and will be replaced and no one except for enthusiasts are going to care it's gone. The V8 will produce more HP, it'll have electrification and it'll meet displacement regulations/taxes in countries like China and India.
Btw, here's another quote from an Autoweek article from last month...
"Company insiders have suggested the Huracan’s replacement will lose that car’s equally charismatic V10 engine, but will instead use a twin-turbocharged V8. Both new cars are set to have electrically powered front axles instead of mechanical all-wheel drive, together with hybrid assistance for their mid-mounted internal combustion engines turning their rear axles."