My approach to what devices to target for mobiles platforms - what do you think?

So me and my partner are in the middle of development of a 2D runner game and we're starting to run into some performance issues on older devices (iPhone4, iPhone3Gs for instance). Now I'm trying to decide where to draw the line. What devices do we decide are the "bottom-line" devices that the game has to run smooth on?

My partner wants to target some older devices, while I have a different approach in mind. Here's my suggestion:
We target high-end devices exclusively. iPhone5 and up, and Android devices running 4.1 and up.
Why? Because we don't know if it's worth putting in the hours to get the game to run smooth on older devices. If we start with high-end devices and when the game is published we notice that people like the game and that the game is profitable, then we can optimize and make the game run on more devices.

So essentially, I'm saying let's publish the game to high-end devices first, and then if the game is profitable, optimize for lower-end devices.

What do you guys think? What devices do you use as "bottom-line" devices?

 

At the time I have not yet released my commercial project -been working on it for a few months-, so take this as coming from an inexperienced source. But this point did cross my mind, and I discarded it. The reason being that I believe that the status of your project at release time is extremely important for the following reasons:

- Reviewers almost always base their review on the product as it is at release time. Sure, you may enhance your product later, but for one, reviewers almost never rewrite their reviews once they've written them once. They MAY release news on the subject later, though, if the product is already a hit, but I believe a lot more people read reviews than they do news.
Also, people reading that review will discard your game altogether once they see it does not work on their device. They most probably will not come back later to check if that changed.

- Users may also forget about your game if, upon first finding it on the app store, see that it will not work on their device.

That said, targeting a minimum of Android 4.1 gives you a huge customer base, at least based on this:
http://stats.unity3d.com/mobile/index-android.html

 

For the "bottom-line" devices:
Don't use the iPhone3Gs it no long in use .
Take a look at the hardware stats by unity they show what is in use today.
http://stats.unity3d.com/mobile/device-ios.html

For the Andorid side, we did not set a low end target.
If it runs on a iPhone 4 and up , android hardware on the same level can run it. (we did test one a Sony xperia play).

Like Razorwings18 said, don't wait for optimization after release.

If you target you game for high end devices because your game play or important graphical details, that's OK.
But don't let people get angy because you game is not well optimized.