By providing value beyond just support. Ubuntu does this via Landscape, Red Hat is still trying to figure this out with Insights and the obtuse licensing for Satellite IMO. Packaging software has a high level of effort but really low value in customers eyes due to how many Linux variants are out there (again, IMO), so putting that behind a paywall these days is dumb. Containers exasperate this problem as most folks don't care if RHEL ships with PostgreSQL, they'll just run the Debian-based container.
For support, folks need enterprise support contracts. Maybe not everyone, maybe not every system, but folks that need it will pay whatever for it, it's the cost of doing business. Charge accordingly.
Out of curiosity, which aspect of the subscription terms do you find obtuse? Simply put, any system managed by Satellite needs to have a Smart Management subscription. You can get these individually, or bundled with a RHEL purchase as the add-on. For consumers of the public cloud marketplace RHEL images, they include the client-side aspect of Smart Management (no Satellite infra, but you can request this) so you don't need extra subscriptions to cover those.
For support, folks need enterprise support contracts. Maybe not everyone, maybe not every system, but folks that need it will pay whatever for it, it's the cost of doing business. Charge accordingly.