Indeed, it would be nice for apple to continue support for PowerPC, it is a fine architecture.
Its dangerous to assume anything in the field of computing without thorough research. There have been many of people debating about "True 64-bit," "Native 64-bit" but I have yet to see anything supportive of either within the debates.
What do you mean by "initially"?, are you saying that Apple considered using the Intel chip or that they used the chip at one time?. Apple never released a product using the Intel chip until the switch in 2006:
Apple I: MOS 6502 @ 1MHz
Apple II: MOS 6502 @ 1MHz
Apple II+: MOS/SynerTek 6502 @ 1MHz
Apple III/III+: SynerTek 6502A @ 2MHz
Apple IIe: MOS/SynerTek 6502 @ 1MHz
Apple IIc/IIc+: SynerTek 65C02 @ 1MHz(IIc), 4MHz (IIc+)
Apple IIe Enhanced/Platinum: SynerTek 65C02 @ 1MHz
Apple IIgs: WDC 65SC816 @ 2.8MHz
Lisa/Lisa2/Mac XL: MC68000 @ 5MHz
Macintosh 128k: MC68000 @ 8MHz
Would you mind giving me a decent example(s) of where the x86 architecture has failed in motion graphics. Where have you heard this?, many computer history texts and documentaries which describe Intel's Microprocessor Endeavor, Intel had no particular vision for its early microprocessor(s) and surveyed those who bought and used their chips to see what purpose they were used for, and to collaborate with their customers to improve the architecture to suit their future purposes. You're referring to memory leaks which are related to bugs in binaries, the x86 architecture is used in many fields throughout the industry and depending on its purpose, its uptime can span years without a reboot and without a hit in performance.