Some of the products you are looking at are made overseas and or in China, resulting in a budget friendly choice if strength is not a top priority.
I haven't added it all up price wise, but for $395 you can get USA made chromo inners from Dutchman Axle. Foote Domestic stock with Dutchman machining.
https://dutchmanaxles.com/front-inner-axle-dana-44-domestic-4340-pr.html
Their 4340 USA made outers are $100 each....
https://dutchmanaxles.com/front-outer-axle-dana-44-import-4340.html
A huge difference is that the Dutchman stuff supports a 1310 u-joint vs the Revolution kit which supports as bigger (stronger) u-joint. Not to say that Dutchman can't get the bigger jointed axle shafts. They source from the same domestic supplier.