If their servers go down, you won't be able to view your balance and you won't be able to create outgoing transactions.
That's not true. There are plenty of clients which you can use to interact with your hardware wallet other than the "official" ones provided by Trezor, Ledger, or others. I only use my hardware wallets with Electrum, for example. The manufacturers could go bust tomorrow and it wouldn't affect me using my hardware wallet in the slightest, other than it would stop being updated.
They also know every UTXO you've ever sent or received. You couldn't develop a better way to spy on Bitcoin users if you tried.
Again, only if you use their software on an internet enabled device. It is completely possible (and in many cases preferable) to use a hardware wallet without using the companies' own software, as wallets like Electrum provide more functionality and more control over your addresses and UTXOs. You can still keep your wallet's firmware up-to-date using the manufacturer's software whilst maintaining your privacy by either doing so on an airgapped machine, or keeping your funds stored behind a passphrase which you do not enter when you update.