The state can be loaded from the SSD, but there is one small problem which always gets in the way. There has to be some program already loaded to load the "state" from disk, and this program gets loaded by another program (the BIOS). It takes some time for the BIOS to initialize the hardware, load the loader, and for the loader to then load the saved state. (In fact there are many steps inbetween those, and this is oversimplified, but you get the idea...)
Instant boot times are possible and in fact were the norm back in many 80's computers. Those computers had their software hard coded into their memory so it only had to be read from a rom chip into ram. The problem is that no software could really be installed to the actual computer system, and updates were near to impossible.
@robotsneedhugs2 and @Osku97
Is that including the BIOS initialization and POST or not? The only SSD computer I have is a linux box, and the BIOS takes the majority of the boot time. The OS boots almost instantly.