Does it really make sense? The gen 5 had very similar models to the 6, though the low power was a 1.6, not a 1.8. The 6 still had a high performance model, like the 5. So in pure performance terms, that surely can't be it. If the points above were right, then how did they manage to sell five gen 5s for every gen 6? Having owned both, there's not really that much difference in terms of driving, power or general ownership terms.
Even the gen 7 managed to outsell the 6, which I thought was surprising, and that never really had a performance model (well, no 4WD or turbo). And the high and low power versions both had the same engine capacity.
I would be nice to get sales figures for gen 1-4 to see if the gen 5 was an outlier in terms of sales, or if the gen 6 doomed the series.
That would kind of suggest it's a one off model unlikely to have a successor.