0f course not. The iPhone 3GS and 4 will support iCloud too. ;-)
Unfortunately, my solution was basically upgrading my Mac, my iPhone and my OS, just like Apple wanted me to do.
There have been a number of third party suggestions here, which are good ones, if you really don't want to upgrade anything. But they aren't perfect, and they are more trouble than I want to go to. I was basically synching via USB and iTunes since I transitioned to iCloud, which finally motivated me to upgrade the phone -- I kept forgetting about appointments because I wasn't syncing everyday, so events weren't being transferred to my iPhone, nor contacts I had added on my iPad, or Mac.
Fortunately the used Apple market offers some acceptable upgrade options for less money than buying new. A 3GS is the minimum configuration for iCloud compatibility, and that is a solid phone, readily available on the used market since it became the "free" phone.
As I expected, Apple is adding back the former Gallery services as PhotoSharing, which appears to require iOS 6 and Mountain Lion. One of the big things I wanted from iCloud was the ability to share my photos easily, but not necessarily post them to Facebook. Perhaps my biggest concern about the original iPhone and 3G is that more than contacts and calendars, I didn't want to lose photos taken on the device, if damaged or lost, and be able to access them if I didn't have my phone. iCloud does this automatically, and imports them into iPhoto, as well as being accessible on iCloud for 30 days, and soon I will be able to select the photos I want to share and automatically make those available to only those people i want to share them with.
All of these things are why I upgraded as Apple hoped. But there are plenty of alternatives to upgraded, just not as seemless as iCloud. Personally, I have been trying to get my phones and PDAs to sync with my Mac since 1995, being forced to switch methods every time I upgraded my phone, or changed carriers, or data devices. I'm just over the days of jerry-rigging a solution that rarely worked reliably and required constant attention to maintence.