Conroe (Core_2_Duo) was after Netburst (P4); next leap was Haswell; and current Intel CPUs could be considered as significant enhanced Skylake.

So, if Netburst gen 7; Conroe gen 8; Haswell gen 9; Skylake gen 10.

Also exists separate branch of Bonnell (Atom), which is based on CMOS old p5 core and have totally different from desktop line generations.

And I don't consider MMX and Netburst as separate generations, but as dead end branches. If consider all dead-ends we should be over 20.

AMD have significantly less number of generations, I think Ryzen could be considered something like k-11.