And do you get to keep that content if WOTC stop supporting Beyond?
Not if Beyond just disappears. That's one reason I kind of like Hero Lab classic, but even that could be an illusion since it depends on the application talking to authentication servers to check your key in some circumstances. Those companies are technically capable of supporting a nice transition into non-existence for their customers, but the way of business doesn't guarantee they'll have the foresight, time, and resources to do that.
In the present situation where there are both online and physical resources, you're likely to be able to go to Amazon or eBay to acquire heavily discounted used books. I see D&D 4e on Amazon for $5.
While still illegal, collapsing support situation might also be a case where a person feels justified in snagging pirated PDFs as well.