ASIC can become trash in months too, Hummer HNS Miner was one of them…
The profitablity depends on Current Hashrate/ Difficulty
If ASIC are introduced for first time in some coins eg. Kadena, Handshake Then Number of Miners produced to matter as they rise the difficulty by folds
GPUs are always profitable as per my view because they have a resale value too and does not turn into an scrap metal like ASIC
S19 will be profitable surely for a year and more, Hashrate is increasing but the BTC Price is also increasing