Square-Enix would bleed money for development costs if it were to go on PS3. Just look how long and much FFXIII is going for on PS3. It's like a double-edged sword or like the Pokemon, "Rampardos," trying to use Head Smash (base damage of 150; Rampardos has a 165 base attack stat), which would be SUICIDE if used; it would give a 50% recoil to it. If the game doesn't sell well, it's going to cost Square-Enix DEARLY and they could file bankruptcy. The FFXIII series is a big budget game.
If Square-Enix were to remake FFVII, it would cost A LOT of money. People know it would be a hit, but how PS3 is currently selling out on the market, it could be either good or bad (if the game were just to be announced, then PS3 would be selling like crazy). We DO NOT know how games will sell; it's the same thing that Nintendo wasn't expecting about the demand for the Wii.
To answer the topic's question, yes, the games can go on other consoles. Even though Square-Enix slept in bed with Sony and produced a lot of different/new Final Fantasy games, it doesn't mean they are LOYAL. It's like a girl wanting money in a man. Nintendo didn't change from cartridge format to CD-ROM because Square-Enix wanted some better stuff. Sony showed off its goods, so Square-Enix left Nintendo to go sleep with Sony. Square-Enix was FIRST with Nintendo, and now that Nintendo is showing that they have what it takes to be successful, Square-Enix will go crawling back to Nintendo because they were with them first and they know that they are a company that will prosper with financial status. Now Square-Enix is unsure about Sony because their marketing is not that stable anymore, they made foolish errors and they are way ahead of their time (with the PS3's power), but Square-Enix will still want a bit of that power (ONLY PS3; not Sony). Square-Enix only WANTS to use a powerful console to make their dreams of a graphically powerful game franchise, in which fantasy becomes a reality. THAT is what we call Final Fantasy, folks.