> Bitcoin is operating at capacity and has shown unwillingness to adjust capacity, so the "kWh/tx" is valid for Bitcoin.
Bitcoin's layer 1 is operating at capacity - different networks make different tradeoffs. Bitcoin has gone the "less change" and "more decentralization" route by keeping layer 1 small, with the goal of moving transaction volume to layer 2.
Bitcoin introduced a number of changes like SegWit that are way more complex than adjusting a constant on layer 1, plus a huge amount of complexity on layer 2 that makes using layer 2 just as complicated as (or more complicated than) using a different cryptocurrency.
Whether it leads to "more decentralization" when everyone can run their own (L1) node but a single L1 transaction costs as much as the node hardware is quite debatable IMO. By making L1 transactions unaffordable, it encourages _centralized_ solutions where IOUs are shuffled around entirely off-chain.
By making L1 transactions cheap, it's basically like giving away cheap, permanent, verifiable storage to anyone which is constantly replicated across the globe.
Even if second layer solutions become highly centralized, the risk is significantly mitigated if you just don't keep your savings on them. If popular second layer solutions become untrustworthy then it would be easy to switch to different ones.
Bitcoin's layer 1 is operating at capacity - different networks make different tradeoffs. Bitcoin has gone the "less change" and "more decentralization" route by keeping layer 1 small, with the goal of moving transaction volume to layer 2.