To be honest, I think we've been asked the wrong question here. Has IGA been robbed of his chance to end his canon? Clearly, he hasn't, because he never intended to end it in the first place.
It's not as if Konami had been preventing IGA from producing a game he was begging to make. In fact, the only glimpse we have of IGA's erstwhile 'future plans' was of that red-eyed Alucard we saw back in TGS 2008. 1999 was clearly out the question, and it would still have been for years into the future had IGA remained in the lead.
More importantly, you really can't compare IGA's 17-year long run to MS's 4-year, 3-title escapade. MS's short, ambitious alternate-timeline reboot doesn't match up with the behemoth of a history the series has. Keep in mind that Konami didn't ask for LoS closure as much as Cox himself mandated it. So telling us that Konami "didn't give IGA a fair chance" doesn't make much sense in this respect.
Of course, whether or not Lords of Shadow's abrupt introduction into the series had been a fair one remains a topic for debate; but there's no denying that IGA had every chance to end his canon if the time was right. I can but assume that for him, it never was.