Yeah, things would be so much better if every 15 year old game were resurrected, ported to the PS2, and stuffed onto a store shelf for $19.99. The ideal PS2 software library would closely resemble the PC software section at Walmart.
That doesn't sound very appealing to me.
If you're one of the 5 people who really care about Metal Slug enough to play it (as opposed to making posts about how wonderful it is on Gaming Age, just because it's trendy), you probably already have access to the game on your Neo-Geo or your emulator anyway.
If someone tried to port Star Control II or Nethack (Sony is just a bunch of haters for not letting games with ANSI graphics on its system!), both games I really like, from PC/3DO to PS2, I'd say the same thing. The last thing I want to see in the video game section is more lame shovelware from companies that for whatever reason aren't capable of actually making new games anymore. If people want to see Metal Slug on PS2, make a new one and sell it to them. Problem is, aside from a few very vocal fans, people don't. Watch the Xbox sales numbers and see for yourself.