A few thoughts, in no particular order:
1. 30 FPS is often an acceptable frame-rate for titles on mobile platforms. Whilst a higher FPS value is obviously preferable, there are realistically only a few types of games that require it, and the main examples of those -- namely, racing games and shooters which require very fast and accurate "twitch" style input -- aren't the sorts of things you would be developing with Construct 2 anyway. If your game has been properly created to be frame-rate independent it really should be playable at 30FPS, and even many professionally created titles made with lower-level technologies are perfectly happy with this sort of performance.
2. 30 FPS with 9 objects does not necessarily translate to lower performance with more than 9 objects. Often beginners increase the complexity of their games to some certain level, notice that the frame-rate is beginning to drop and assume that anything more complex will be out of the question, but in reality that depends on a number of factors, and unless you've actually tested to be sure it's entirely possible that you could conceivably add quite a few more objects without (or with only minimal) further drop in performance.
...and as noted above, for a huge variety of games ~30FPS should be good enough for a playable game.
3. Other people have successfully created games with Construct 2 that perform acceptably well on the platforms in question. There are limitations to every system, Construct 2 being no exception, but the fact that other people have succeeded shows that it can be done if you have sensible goals and do things correctly.
4. "Go try something else" is a terrible response. Construct 2 is Ashley and Tom's livelihood, and unless they are able to make a living with it they won't be able to continue their fantastic efforts of constantly adding features and improving things. It really doesn't help them to suggest that someone who complains should just go elsewhere.
It's frustrating when things don't work the way you want, but rather than screaming "scam" it's pretty likely you can actually solve your problem. Making (good) games is hard, no matter how you do it, and whilst an editor like Construct 2 makes the process a lot easier you still have a lot of work to do yourself if you want to create a good game that performs well -- especially if you're targeting a mobile platform with limited capabilities.
Follow the recommended best practices, try the performance tips, and if you're still having trouble ask for community input.