As a likewise amateur cryptographer (in order words, take with more than a pinch of salt), I disagree with
As a thought experiment to test the above quoted claim, imagine that I (as receiver) generate 1000 RSA key pairs and I meet in person with the sender (Alice) to hand over the 1000 public keys.
Each time Alice wants to send me a message, she picks any available public key, sends the public key, encrypts the message with the public key, sends the result. She then discards the public key (so that she can never reuse it).
So this (slightly artificial example) meets the condition of never reusing a key but if a quantum computer can break RSA (dependent on the difficulty of factoring a large number that is the product of two large prime numbers) then clearly the above scheme is broken.
It is not reuse that is the problem. It is just that the algorithm is (hypothetically) quantum broken.
The message itself may even be shorter than the length of the public key. (Alternatively, you can break the message up into submessages and ensure that each submessage is not longer than the key and use as many keys, one per submessage, as needed.)