About 10 million XP a week is a reasonable rate of advancement in this game. That's about a year to get enough XP to GM all skills, and then about another year to take 2-3 trees to 120. Taking a 4x innate to 150 will take about a year as well. You'd still have to play for over 30 years to take a single 1x skill to 200 on those gains. Getting people to play a game consistently for several years is more useful to a game than to get them to grind like crazy for a few months, or simply quit when they realize grinding is the only real way to raise the XP they need.