Actually no.
If you want proper security for your coins you have to start with a setup where the seed or private key(s) never get into the online world.
This means hardware wallet, or an offline computer or signing device, but also means the seed backups are done and stored properly (offline, pen and paper, ..)
Reading this comment defines everything I wanted to say as I read just the title of this thread.
But if I should say what I wanted to say in another manner, @OP, I would tell you that obtaining good Bitcoin security measures lies in the hands and knowledge of the Bitcoin investor. Come to think of it, it's possible to have strong PC and mobile device security like you have said, but would you agree with me that a Bitcoiner can still carelessly leak the security phrase of their wallet to the public? There are many ways a Bitcoiner can expose their security information without even realizing it, and it's a lack of proper knowledge and other mistakes that causes that. That's why, as I said above, to obtain an optimal level of security, it is in the hands of the Bitcoiner.
Someone can have the best security device in the world, but once they mistakenly download any malware unknown to them, they are finished. Hackers have different ways to attack your device; it could be through emails, receiving any file, or even downloading an image. Keep your detail offline like @NeuroticFish have said, and you will be safe.