you’re saying a buzz word without understanding the trade offs in designs… POW doesn’t have to imply higher energy cost for more transactions: shove more transactions in a block and POW cost is the same… that’s a trade off sure because then a block becomes a more valuable thing to 51%
POW is also only 1 of a lot of different consensus algorithms, all with their own trade-offs… POS benefits those with money for example (although you can still form mining pools - TBH i’d argue it’s exactly the same in this respect to POW in practice - good luck mining anything of value in POW without investing $ millions)
some blockchains aren’t built to be entirely trustless and uncoordinated, merely semi trusted and loosely coordinated (think a consortium of banks - they don’t trust each other entirely but a blockchain means no individual member working alone can cheat. in this case because it’s semi-organised they can use POS with a special token and delegate those “mining tokens” 1 per member of the consortium or something… you can even set this kind of chain up as an ethereum side chain!)