the lack of flair has definitely disinterested the older generations in France. My dad only likes it when teams play without going to ground every single pass; he's in constant poetry mode when he watches the current all-blacks, can't quit lauding their prowess to keep the ball alive and play a fluid running style. He's obviously stuck in his own days when attacking was such a huge part of the game, especially back when he was in France watching the good stuff as it happened. So I think he represents the nostalgic older generation quite well. The younger generation, we're all about stats, super pedantic/accurate analysis etc...and the game has turned extremely serious in very little time.
But although the style in France has been rendered more rigid and pragmatic, backs still kept that French style of beating defenders, looking for mismatches, footwork...I'm not going to enumerate names because they basically all play like that in France. But it's the systems indeed that limit that sort of play.
Whether the number of fans has risen or dropped, I'm not sure, but the fanbase still is very potent in the country so I'm not worried...
We do, even the younger generation, long for more flair, that's for sure. It's constantly, constantly brought up.