I keep my Bitcoin air gapped as I think it's safer than on Trezor that requires regular firmware updates.. The Trezor wallet is only for smaller amounts as quicker to sign a transaction. Yes I will buy another Trezor should it fail, but I like knowing the seed words and pass phrase also work on an air gapped Electrum wallet.
So you think that Electrum wallet and operating system on your computer doesn't need any updates? 
You don't have to update Trezor device if you don't want to do it, except if there is some serious security issue with old firmware.