So the UI design of SAP is user hostile. Even by embracing modern web components and openUI toolkit SAP will continue to be user hostile design.
SAP will need to change the foundations completely to change it and also re do things. But then it will put them in direct competition with modern software makers who can beat them.
So I am doubtful things will change, SAP will go the path of IBM in times to come.
It's what happens when the users have no choice in the matter, there is no reasonable alternative or competition - therefore no incentive to change or improve.
Whether it's intentionally designed to be user-hostile, I've suspected (and doubted) that myself.. There might be a logical explanation how that's desirable or even profitable, as a kind of moat or gate-keeping.
With its legacy and massive complexity, SAP would require a visionary to re-architect it from the ground up. Unfortunately, that rarely happens in enterprise software.
We can only hope that scrappy startups arise to replace and evolve.
It is certainly not true that SAP does not care about UX (in fact the reason why SAPgui has it's decidedly non-native look is result of some UX research in late 90's), only the UX they care about is not about easy onboarding, but about efficiency of use. And by the way in my opinion SAPgui manages exceptionally well to combine power user features with discoverability (on the UI toolkit level).
This generation has options for creating full custom software faster than one can configure an ERP.
No we can't do that, because the real world is messy. I currently work on a SAP system and the amount of localization and customization that was done for you is inexpensive for big corp. And you know that SAP will last the next 30 years, you don't know that about your Framework of choice.
Up until some 5 years back, UX really was afterthought to them. Why? Answer is in how enterprise software was (and largely still) sold. Buying was done by CIO, based on all parameters (account relationship, FOMO, $$$ discounts, functional reliability etc.) except user acceptance.
SAP simply didn't have incentive and KPI to see UX as focus. Users were "trained" to use SAP after rollouts.
With what is fancy termed as "consumerization of IT", SAP has been forced to change. They've been trying their best with Fiori v1, v2, v3 since then. Change takes time to get hold in SAP world, specially given large on-premise installed base, where customers take years to adopt a release upgrade.