PlayStation 2 Dilemma

It definitely depends on what game catalog you want to play. If you have a big collection of PS2 games, a PS3 won't do you any good unless it's a really old model that has PS2 backwards compatibility. They're extremely rare and expensive now (mine died out about three years ago, had to get replacement without PS2 disk compatibility). PS3 has a pretty decent selection of PS2 games available for digital download, though you'd have to re-buy those. I know you know this already, but I'm unsure what your goal is.

At this point though, unless you want to play very obscure games, I think getting a PS4 Slim is your best bet. A brand new console for $300 is a great deal. Especially now that the entire Kingdom Hearts series will be available on it in less than five months. And if they continue adding classic PS2 games on there, then that's even better (I love me some War of the Monsters).

It really is a shame that the games industry suffers from this problem. Having to jump through hoops like this, scouring ebay or wherever, is expensive, time-consuming, and a gamble. If you fancy yourself a collector that's another thing, but for the average person, especially if money is tight, there are more sensible ways. To be clear I'm not condoning piracy, but if the damn things aren't being made anymore, legal emulation is an excellent alternative.

Again, depends on your circumstances and what games you actually want to play. You're the only one who can really decide. It's great that you still have your PS2 around, but nothing lasts forever. Not sure if you've made your purchase yet or not, but you should for sure research which PS2 games they have available on PS3/4 that you'd want. And also consider what games are coming out in the future that you might want. Obviously nothing is future proof, but I'm somewhat optimistic that the industry as a whole will be more mindful of maintaining compatibility into the future. With iterative consoles like the PS4 Pro and XB1 Scorpio, it's quite possible that old games won't become obsolete anymore, or at least not for a very long time. This console generation has been very successful, and I honestly think it's worth investing in. PS4 will likely be around for a very long time, and while PS3 is still a good choice, I think there are great benefits to being in sync with the current generation, especially if it's relatively inexpensive.