>the content adapt to it by increasing the frame rate
Like I said before, there's only two ways to do this: Either synthesize fake frames using a computer (software like SVP), which will of course result in artifacts and latency, or originate and store content at a higher framerate (MUCH higher, like hundreds of FPS). If you have low-FPS content and don't want artifacts or lag, flicker is the only solution.
>you can have top class IPS today with 2 (I've only seen 1 in TN and never saw 0).
I don't think LCD manufacturer figures are credible. For instance, while this was back in 2009, an LCD rated as "8ms response" yielded 2x-4x that much lag, depending on GtG conditions, when actually tested:
And attempting to get around this by switching from slow laggy tech like IPS to something faster (less slow, really) like VA, TN, or BPM, means sacrificing even more of LCD's already inadequate color/tone performance. LCD is just absolute garbage in every way.