Unsound, what you say is normally correct, but if a person wishes to go the tube route and has incompatible speakers for tubes shouldn't fellow members here tell the potential tube buyer that information? Then he can go find the speakers that he likes that are synergistic with tubes; and by-the-way, many people know for example that they prefer tubes to SS after hearing tubes, but might not understand that their current speakers are not a match made in heaven, so, the reverse of your normally correct theory is reversed. As the old saying goes, " more than one way to skin a cat."
I knew that I wanted SET 300B sound, loved the Cary house sound, bought the amp and went out and found the right speakers to match up with them, not more difficult to do than the other way around.