You don't have to constantly stream it if you don't want to. You can download any tracks in your iTunes Match library to local storage on your device. If you know you're going to want xAlbum on your phone, download it (using your iPhone, iPad or computer) and listen to it. But I just don't understand the necessity of having every song with you at all times.
That's like saying we should all buy the new 8GB 5C and if we know what apps we'll need we can download them as we need them and delete them when we're done. People shouldn't have to do that. When I'm driving or at work listening to music the last thing I want to do is worry about downloading something. Not only is inconvenient but it takes the spontaneity out of it. It may be wishful thinking but 128GB is not out of the realm of possibility. Unlikely, yes, IMO, but a somewhat reasonable expecctation. I would assume most of the people asking for 128GB are willing to pay and pay well for it. They're not trying to force a higher cost option onto those that don't want it and they're not necessarily expecting Apple to offer it at the current 64GB price point. We want it and we're willing to pay for it. It's just frustrating when Apple won't take the extra money we're begging to throw at them.