Trezor has solved Bitcoin's security problems in the same way that PGP has solved internet messaging security; that is, amazing technology exists that addresses real problems, but in practice the problems are still prominent. Security is a major problem for the internet, and a much bigger problem for bitcoin since the incumbent system provides nearly identical services with a substantially smaller risk of losing real money.
Trezor has solved Bitcoin's security problems in the same way that PGP has solved internet messaging security; that is, amazing technology exists that addresses real problems, but in practice the problems are still prominent. Security is a major problem for the internet, and a much bigger problem for bitcoin since the incumbent system provides nearly identical services with a substantially smaller risk of losing real money.