Hmmm. I don't think so, but I may be wrong. Let's see:
My long-term campaign has a party of 6 characters. They made it from level 1 to level 12 in about two and a half years, after 80 6-hour sessions (less than a year of in-game time). So, 11 levels gained over 80 sessions, or approximately 7 sessions per level. Hmmm. That doesn't sound right.
However, I think almost every player has skipped at least 15-20 sessions, which reduces the number to 6 sessions per level. The ones who have skipped only a couple of sessions have changed characters, so that accounts for their lower level. About 10 sessions were either spent playing alternate characters or were interrupted. So, realistically speaking, it's 5 sessions per level. That seems OK.
I also allow players to purchase feats with XP, and most have done that, so that has probably reduced the level a bit, as have the few deaths and casting spells with xp components. Overall, I'd say they were gaining a level every 3-4 sessions at lower levels, but it takes them a lot longer now (as it should be, IMO).
As for the amount of gear, they have less than what is recommended for their character level, but not a whole lot less. They are about a level behind, I think, but their combat ability hasn't suffered because of it.