I'd like to defend SE a minute. Just hear me out.
When SE says they can't "fit" the remake into a single release, they don't mean in the physical sense (they could obviously create as many discs as they wanted), they mean that they need a lot of time to create the amount of content that they want to make. It sounds like they want to spend something like 6 years making all the content, and they don't want to make the fans wait that long.
Suppose you were given two choices: (a) SE spends 6+ years making an epic, huge remake with tons of content and expanding on the FF7 universe, etc., or (b) Square Enix spends 2 years making a remake with limited scope. Which do you think most FF7 fans would choose? If they go with (b), a lot of fans will surely be disappointed and want a lot more and wish that SE spent more time on it, given how special this game is. So, SE is obviously going to choose (a).
Now, suppose SE decides they're going to spend 6 years making an epic remake. I think it's perfectly reasonable to charge more than the cost of a single game for 6 years of development. And I like the idea of splitting it up into parts so that we don't have to wait 6 years. (For example, split it into 3 games, 2 years apart each.) A lot of people say they don't want to play it until all parts are done, and that's totally understandable, but they can still do that even if SE releases it in parts, by waiting until the last part is released.
However, I will acknowledge there's a possibility that SE could do something like "release part 1 of 3", then "release part 2 of 3", then instead of "release part 3 of 3", they might do something like "release Crisis Core prequel remake", then "release other expansions", blah blah blah, then finally wait to "release part 3 of 3" until the very end, making such people wait for a very very long time until the whole thing is complete. But, hey, if you have the desire and willpower to wait 6 years, you can probably do 10 years just as easily.
By the way, obviously this is just an example, we don't know many years they'll take, how many parts there will be, how long we'll have to wait between parts, whether we can use our game data from one part to the next, whether there will be level caps, etc. So, it's kind of early to pass judgment until we have more information anyway.
