Most people don’t realize ABC has been wanting to cancel his show...

We know in one case (for The Late Show with Stephen Colbert) that it was reported to cost over US$100 million/year to produce and allegedly lose ~$40 million/year — though Jimmy Kimmel himself disputed that figure.
Given the show still ranks second among late-night shows in many metrics, holds some value, and likely brings in more than simply its viewership count (e.g. ad/affiliate revenue, digital clips), cancellation might save some money. But whether it saves more than it costs (including opportunity cost, brand, etc.) is uncertain and probably marginal unless the decline is very sharp.
