They went wrong because once the product became data, then it became a commodity whose price naturally wanted to collapse to the marginal cost of production (for data, very very low).

There will always be a market for entertainers to produce live performances and bespoke works, and that market doesn't require DRM because the product is intrinsically uncopyable.

Likewise, source code is just data. You can't really sell source code. You have to find something else, something intrinsically uncopyable, and sell that instead.