We agree, that a longer period is more indicative of a trader's overall performance. It is after all a long form game, if you want to trade for a living. However, there needs to be some sort of evaluation mechanism that shows the abilities of a trader, without asking them to commit to virtual trading for years, before they receive their opportunity. 60 days is where we arrived with Helios, the prop firm which is our first partner. We are in fact working on longer Gauntlet™ at the moment.
If you have a long enough trading history that you can show to Helios, do contact them and they might take you on. If you don't have that however, for lack of funds that you could have traded with, the Gauntlet™ is a good solution.
It is also worth mentioning, that the prop firm can increase the account the trader is working with, depending on the trader's performance and consistency over time.