No, this is a completely wrong conclusion and I believe you know this. You can trust your ears to determine what sounds good to you, that is it. No different than trusting your taste buds to determine if you will like the taste of that chocolate bar you bit into.
Measurements determine the actual performance and accuracy of a speaker. They are an excellent visual representation of speaker performance. No different in needing the actual ingredients and percentages of the ingredients to determine if that chocolate bar is healthy for you.
You have been trying to trust your own hearing with sine-wave test tones to determine the measurements of a speaker.
Would you trust your taste buds to determine the ingredients and the amount of those ingredients? Of course not, not even professional chefs can do this.
When you have accurate measurements of a speaker that you like, if a different speaker measures very similarly, you can make the assumption you will like that speaker too. If there are aspects of a speaker you don't like - after properly measuring the speaker and playing with equalization, you can then take steps to improve what sounds better to you. Or, if you are after absolute accuracy, you can use the measurements to apply EQ to help tame room issues or correct problematic response issue with the speakers.
Do not assume accuracy and what sounds good to you are one in the same. (they are never related)
Because then you haven't actually learned anything and have no baseline of determining what frequency response sounds good to you.
Trust me when I say this, the measurements you will see will indeed show a VASTLY different response than what you think you hear. You have already proved this in a previous statement you made, which I quote above. You won't be happy, but you will be on your way to learning more.