This is disappointing to hear. When Jet was acquired, I thought a significant motivation (and justification for acquisition price) was to give Walmart access to the Jet’s tech stack. Apparently this was not the case.
Across the Walmart.com websites I didn't see anything from jet tech. The only thing I heard talk of was essentially reporting to push Marc's basket economics passion.
I believe Jet's acquisition was essentially a way to buy Marc Lore as eCommerce CEO.
I've met with many Jet folks and they are an awesome crew to work with, but Jet didn't really operate at Walmart scale.
Disclaimer: The accuracy of this should be taken with a grain of salt, I wasn't involved with any of the decision making.
Both the distribution centers and the technology driving them have been integrated with Walmart systems early on after acquisition and many current and future developments in that area are based around formerly Jet tech written in F#.
That's not going anywhere.