Now now, people in glass houses shouldn't throw stones. What is the marginal return of one CPU hour mining on your favorite fork just a few weeks after it started? Bitcoin's difficulty hasn't ever grown faster than doubling in a month or so, it's never been a gigantic bonza where someone a few weeks before you was getting 100x more. It wasn't launched with a difficulty thousands of times below what the surrounding network could support (quite the opposite: the bitcoin network wasn't fast enough to justify the minimum difficulty in the first year).
The difficulty in the cryptnote implementation adjusts every block and pretty fast in practice. The block times stay close to the target. In fact you look at the overall block rate on all of these coins since launch they are pretty close to the target in terms of blocks mined per day.
There are definitely shitcoins that are launched with diff 1 and lousy adjustment algorithms that mine off absurd number of blocks on the first day or week until an adjustment hits but that is not the case here at all.
Sure, if people find these coins attractive and begin using them the difficulty (and likely the value) goes up but that is not guaranteed nor is it a one-way street at all. Monero and Bytecoin have had significant drops in difficulty and value as popularity and value ebbs and flows over the past month (I can't really speak for the others since I don't follow them, but I would guess the same).