Yes it is rare to see transaction still left in mempool for almost 1-2 years but it is much possible either by the user himself rebroadcasting it regularly and the fee as stated above or the wallet used as an inbuilt rebroadcast which it does regularly.
It doesn't even need to be rebroadcast.
We know for a fact there are some nodes which run with much higher limits than the default. If you look at
https://mempool.space/ for example, their node is showing over 1 GB of memory use, far beyond the 300 MB default, and the graph is still showing all transactions down to 1 sats/vbyte. If you look at
https://jochen-hoenicke.de/queue/#BTC,1w,weight,0, his node is keeping all transactions, even those paying less than 1 sat/vbyte in fees. There will be many other such nodes which will hold on to OP's transaction indefinitely.
Still, his transaction pays 12 sats/vbyte, so it won't take a year for fees to drop back down to that level.