It has always been doable.
There are two problems.
1) There is no microcode for the newer CPU's (AMD/Intel) available for Windows 7. It is not actually required, as Windows will fall back to x86 mode (80386 compatible), which limits a lot of the potential performance gains a newer CPU could bring.
2) There are no motherboard chipset drivers for the later chipsets required to allow the new CPU's to run. Again, Windows will fall back to x86 mode which places a lot of limitations in the performance of the chipsets and also eliminates any newer technology available in the new chipsets.
Bottom line: Sure you can run the new CPU/chipsets, but chances are you are going to give up performance in doing so. Some functionality will go away as well, like USB 3.1.
Getting around Microsoft's block of updates is trivial, but those updates will not install the drivers which do not exist.
It really is a waste of time.