> Each subsequent block in the chain gets larger, increasing the cost of the necessary resources to sustain the cryptocurrency.

That's not correct.

The effort put into any block, past and future, is (long-term adjusted) directly connected to the payout, since the effort is algorithmically self-adjusting. It follows, that the effort put into any current block is worth ~$300k, and therefore worth ~$300k of electricity.

If bitcoin is ever going to be valued less again, the necessary resources to sustain bitcoin will shrink accordingly.

Additionally, they automatically shrink, by design, in ~2024, ~2028 and ~2032.