the only thing ford did to tarnish jag was releasing a warmed-over mondeo as a jag. ford picked the right problem to solve at the start: jag's quality. problem is, after that was fixed ford had no clue what to do next.
jag needed 5 year product cycles and a top to bottom line up. it had neither.
ford let the s-type go from competitive to ancient (1998-2007). the xj was already old when ford bought jag, and it continued on (while ford fixed the quality issues) for another decade (1986-2001). the xk was redesigned shortly after ford bought jag, but also went a decade (1996-2005). you can't compete in the luxury market (or any other market, really) if your cars age double digits before they're remade. and now the XF (s-type replacement) is supposed to be on a modified s-type chassis? i don't know if that's a recipe for success (though the XF is hot).
additionally, it's hard to sell cars when the cheapest real jag competes with the 5 series and e-class. and because the s-type is so old, their only competitive product offering is the XJ, an S-class, 7 series, and LS competitor. you can't become a 200,000 car per year brand when you're only competing in the $80,000+ market. it also doesn't help that jag has been using the same engines for the last decade (though with minor updates, the AJ-V8 isn't a bad engine but without the blower it isn't up to par against the LS460)
