Forza Motorsport sales evolution and future?

[DonFerrari]

FM1      FW --         FM --        LTD 1.05M        HW at launch Xbox original --

FM2      FW 14k     FM 550k  LTD 4.05M        HW at launch X360 @ 10M (stablished a strong franchise after weak release) - debut as 42th

FM3      FW  210k  FM 0.9M LTD 5.49M        HW at launch X360 @ 33M (increased all sales metrics) - debut as 7th

FM4      FW  515k  FM 1M     LTD 4.57M        HW at launch X360 @58M (more frontloaded but a little smaller LT) - debut as 1st

FM5      FW  326k  FM 640k  LTD 2.31M        HW at launch X1 @ 1M      (being of decline, but new generation could explain) - debut as 6th

FM6      FW  221k  FM 440k  LTD 2M             HW at launch X1 @ 14.4M (dropped a little after the previous tittle even with more userbase) - debut 2nd

FM7      FW       FM      LTD         HW at launch - all not available yet, but amazon, UK and Japan ranks aren't high at the moment.

Had it appex at X360 in FM3 and stayed strong, but declined severely on X1, have the userbase migrated to FH, PS4 or excessive iterations made it lost appeal? Also used to debut at top of the week sellers but dropped from ranking.

 

FH1      FW  316k     FM  578k    LTD 2M        HW at launch X360 @ 71M -debut as 2nd

FH2      FW  88k@X360+235k@X1     FM 168k@X360+367k@X1     LTD 0.8M@X360+1.41M@X1  HW at launch X360@83M, X1@6M - rank 7th and 12th (4th if consolidated)

FH3      FW  406k     FM 680k    LTD 2.54M     HW at launch X1 @ 23M  - debut at 3rd

Forza Horizon have kept steady and constant sales (accross FW, FM and LT) and transition from X360 to X1 and now is ahead of the original Forza Motorsport.

 

So what are yours perspectives for the future of the franchise?