For most big tech companies, apps don't really matter. Your decision on your bank, streaming services, ISP, hardware vendor, etc isn't primarily driven by app quality, it's driven by other factors. "has a beautiful and thoughtful app" is not high on the vast majority of current and potential customers decision criteria. Apps are a cost center and a marketing channel, and are at this point quite often left to languish until they're bad enough to be fully replaced. They are not continually improved, refined, etc. Apps are expensive to produce and require constant maintenance, as both OS and user expectations change.
For a tiny indy shop the app may well be the whole business, and so is invested in accordingly. For a giant company, why spend money on something that just doesn't matter?