Most of the "frame rate" issues with PCs fall into two main categories, imo.
1. A lot of mid-range PCs currently in use. These were 'beast' PCs compared to the 360/PS3 so people never upgraded them much. Newer games are now made for the Xbox 1/PS4 standard. These mid-range PCs are no longer adequate and need upgraded.
2. The current 'beast' PCs that have problems are almost ALWAYS SLI users. They think because they have 2 GPUs that they should handle anything. Well, the truth is that without a proper SLI profile for a specific game, 2 almost always work worse than one.
These tend to be the two main groups complaining about frame rate issues with some of the recent games.
I have a 970gtx and have had no frame rate issues on any games recently, including Xcom 2 and FC:Primal. Both of which have their forums flooded with complaints.