One could argue that LHR should get a Polaris lounge first because it has way more international departures than DEN does. I personally think that it’s a long ways off, as I do think (as noted above) that the O/D demand for nonstop international travel needs to exist, and DEN simply doesn’t have relevant lift there to support it. Maybe the calculus changes if they add more TATL flights (e.g. CDG, BCN; I do not see any TPAC flights being added unless they can somehow market DEN-AKL or DEN-CHC to people who want to go ski in the northern summer to locals), but again - hard to see where the level of flights gets to something where that will happen.