People resign for real reasons like operational turmoil, job insecurity, and personnel conflicts, not for being focused to develop on a slightly older platform (for which they'd still be developing assuming DC had lasted a normal console cycle and for which they still felt had performance headroom) over marginally more powerful machines, especially in Japan's worrysome economy. If console performance was a driving factor, there would have been resignations when the PS2 was focused on over the Xbox. SEGA designers most preferred the huge leaps their new generation hardware provided them throughout the years, but it's really just been about pushing hardware designed by their company and with input taken from they themselves and about keeping it competitive.