How important is support for older devices?

I just realized that my game has some (memory) problems with older devices. I installed it on a iPhone 4s and when a larger scene is loaded the game lags for half a second. Lately I had this obsession to test all released Buildbox games on this older device and several have issues. For example Pumpkin Man's Wild ride from @ajcoryat doesn't open at all (it crashes with the loading screen). Almost Impossible by @dan_counsell does not have any light effects but works otherwise great. And the new released Shadows by Daily Life Apps and Buildbox Games (@Aaron F) for an unknown strange reason does not disable the lights but lags that much that the game is not usable at all. Others like Darthy by @cbecks noble works pretty good (and I think there are some pretty large scenes too?). And @TreySmith classic, Phases, lags also from time to time very much.

If a iPhone 4s lags, then I think on older (and most) Android devices the lag will be there too. But how important is it to support this devices? I think in the US not that much because a lot of people always get the new devices. But in other countries probably this is not the case. Then, what about the bad reviews which can have an impact on downloads in general? I remember a lot of bad reviews for the game Phases regarding level 4 for example.

In short, I have no idea if I should keep worry about older devices and change my game structure and gameplay to something that works or if I just should keep going. And if I keep going, would it be best to announce the game that way? Something in the description like: This game works only with iPhone 5 and later because of memory issues...?

Ah, and another thing I realized some days ago: banner ads during the game always make it lag. Is it better to disable them completely to assure a good experience?

 

Must admit, I never tested on the iPhone4.
Presently (as at Nov 15th, 2015), the iPhone 4S represents 6.4% of the iDevice user Market. iPhone 6 is 16%. 5S is 11.8%
When sorted by iPhone Stats only: iPhone 6 is 26% and 4S is 10.5%, 5S is 19.2%
Really useful data available here

 

Thanks for the link. Very interesting. I suppose this are global stats?

I definitely wouldn't care for the iPhone 4 and older devices (no ios9 either). But the 4s still seems to be very important. I think in a lot of countries they give the 4s as a free phone when buying a contract. I'm surprised how good the ipad 2G is doing.