They want to get more people in and more profit from fees. Setting up a pool is probably more profitable than mining. At 3% pool fee a 1000mhash/s pool operator will make as much as someone mining on a 30mhash/s rig.
I've noticed many of the pool admins spamming these threads with their pool advertisements, telling how they have 32 cpu cores, ssd drives, etc, but from ip lookup it seems they're running off some cloud virtual private server operator that doesn't offer anything like they've described.
Stratum is really lightweight for the server, but the database is under a heavy load. The usual MPOS frontend stresses the DB quite a lot too when it's trying to show the statistics to all users. There's lots of room for improvement, like modifying or rewriting stratum+mpos to use for example Redis to store the fast moving data.
Even some of the multipools run from amazon or digitalocean and are doing just fine. Probably a couple of virtual machines with more expensive plans. These scam pool operators are not running what they advertise and are probably running on the cheapest vps and the specs are nowhere near what they post here.
Probably 70 to 80 percent of them are running the cheapest possible setup too. I totally agree, the database is the hardest thing to maintain, but should be the priority of these pools to make the backups and secure ones at that.
There's got to be a rating system and/or sorting process before these pools can setup, and officially accepted from the coin creators/devs. Some sort of seal of approval.
Totally, these pools make the most money per investment on these pools, even charging 2% is still a good profit plus the withdrawal fees too.