The strategy is more about reaching different customers, and gobbling up potential competitors while they are small. The frontends may look a lot different, but its all one backend (or at least that is the end state for these acquired companies).
From my perspective, Walmart.com is finally seeing customer facing improvements as they have finally completed the backend re-write and migration which took literal years and held up most customer-facing work. Rewriting the FE, while not a small undertaking, is actually not that difficult to do with their architecture. Compare that to say Amazon, who I interviewed with, and they admitted that changing say the "Amazon orange"color to something else would be a herculean effort involving a year of planning across the entire company and lock step releases across the company. They seemed to think they had a better way of doing things, but after hearing that, I wasn't so sure I wanted to work there.
Honestly the whole recruiting process had turned me off. They had reached out to me, and they baited me with the run the "front page of amazon" hook. I knew things were not headed in a great direction where I was, and it was right before bonus/vesting, so while I was not yet actively looking, I said just have a talk, make some contacts there. The recruiter I spoke to was unlike any I had spoken to, he felt like he worked out of a call center. He made it clear the position was based out of Austin, and I wasn't looking to relocate. It also became clear to me that this guy was just trying to fill this role, he had zero interest in trying to see what else was open where I might fit. Even though I wasn't looking to relocate, I figured I could wow them and either get them to relent on relocation or find a more local role that would fit. 6 months and several rounds later I finally get an on-site. At this point though, I had started actively looking, and by the time I got on the plane, had 3 offers in hand. I wouldn't have gotten on the plane, but I did kind of want to see the process through, I had never been to Seattle before and had a friend there.
I was really disappointed in the whole thing really, particularly their recruiting process.