Bitcoin shouldn't have anything but base58 addresses that begin with an 1.
Then tell me, should it have P2PK? Because in the Genesis Block, and in many blocks after it, coins were sent to public keys, not addresses.
the fact that an attacker needs less bits to steal all funds vs a non-HD wallet has not been disputed
Of course, because every HD wallet is in practice a single key, that is expanded in deterministic way. And if you somehow break that key, then you will access everything. But good luck with that. The famous puzzle from transaction
08389f34c98c606322740c0be6a7125d9860bb8d5cb182c02f98461e5fa6cd15 also used HD wallet.
And more than that: public keys from 161-bit to 256-bit range were revealed. Many private keys with lower ranges, up to 70-bit, are known. So what? Over 900 BTC is waiting for you, so just break a single key, and grab them all. Hmm, you don't know how? Well, maybe because it is not so easy, to compromise a HD wallet. So, don't worry too much about HD wallet security. This challenge can prove you, that HD wallets can be safe, otherwise you would sweep all of that instantly, if you would know some weakness.
no excuse to not support it
But they are supported. You can have a descriptor wallet, and load each and every key from WIF manually. So, what exactly is your problem?