First you don't **have** to consolidate. coinjoin / payjoin features can be implemented in the future to address this concern, but it's not an issue in almost the cases if you use your wallet frequently. It can be costly at some point if fee really get night, but that's the currently only/better way imho, with the actual state of bitcoin, to address problems we trying to solve.
Discussion
So if you have let's say 20 UTXO which you didn't spent from you just do 20 separate transactions after one year at the same time? Isn't it very obvious that the transactions come from the same wallet? Also it's 20 times the transaction fee in the future which is very uncertain, right?
Yeah 20 separate tx, but I'd not do at the same time.
Yes it can have a cost to renew, it's always a question of tradeoff. I personally feel the price to pay is cheap for the "safety net" feature, and nobody forced to use a system ala Liana.
Maybe a good feature would be to randomly create transactions to renew the coins, so there is no pattern to spot for chain surveillance. Similar to how Jam does it.