Nothing is refunded

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Decision#

Rollback restores state, never consumed resources:

a failed call or transaction keeps everything it consumed;
G counts gross allocation, so deleting a record earns nothing back and recreating it pays again;
D counts output when it is generated, even if a failing caller discards it.

The work was done. Every validator executed those instructions, read those records and produced those bytes. Counters describe work, and the work does not disappear on rollback.
No recycling. If rollback restored counters, a transaction could allocate, revert and allocate again, or generate output and discard it, doing far more work than its budget shows. Monotonic counters make the receipt an honest bound on what validating the transaction cost.
Simple, checkable totals. Block totals are plain sums of what transactions used, which every node can verify independently.

Failing late is expensive, so programs should check cheap conditions first.
A transaction that runs out of budget still pays for everything up to that point, and its receipt says so.

Patterns that use temporary storage as scratch space pay full growth for it. Programs keep temporary data in memory instead.