The Full price of a one-year subscription for Fusion 360 Machining is $2145 ($545+$1600).
That is 100% correct, so the four and five axis functions add VERY considerably to the price of Fusion, and as you say it is an annual subscription.

I compared at the time with others including VisualCAM and at that time it was $5000 perpetual for four and five axis plus an annual maintenance (optional)
The listing on their website suggests a price range of $595 to $10,000 depending on the functionality required. I rather suspect if you want full five axis the cost
is closer to $10,000. It may well be, as has been posted, that fourth axis functionality is rather less.

I concluded, maybe wrongly, but I did study it that Fusion was fair value, and as there are other features of Fusion, especially the Electronics and PCB module that are essential
to my business.

I too was rather surprised at the cost of four and five axis functionality, most of the software that I looked at wanted $5000 or more for a perpetual license plus an annual maintenance fee.
I think the bottom line is that four and five axis is expensive.....and they're all like that as far as I can tell.