Hi, have you ever thought this?
You know that, to import a wallet you need the private key or your seed. Taking as example the private key (the 52 letters key). It could exist the possibility someone create a software whose function was to try thousands of times to find the private key till it is be done.This would be like the process to find the new block in mining, anyway you can try the times you want in order to find it.
I think this could be a weakness, correct me if I am wrong.

Or comment if you have a kind of solution for this...
Regards!
Stealing is really possible. It's just that there are different cases that it might happen. We all know that the private keys are made for security. Every code is very unique and the chances of stealing are very small. Hence, if you are the one who lost your private keys or forgot them then it could be of a really bad idea. While if your coins are lost then it will contribute to bitcoins value but it is not considered as a stole. So people, must always take good care of their accounts to prevent such things.