If we are to become nit-picky, it should state "I want to thank the millions of Americans who supported my husband and I over the past 4 years and have shown the incredible impact..."
Also, just changing "shown" to "showed" works. Passive voice is frowned upon, grammatically. For her to be acknowledging she will no longer be FLOTUS, it should be "showed". Closes the door on the future. Clearly past tense.
The fact she used "shown" hints passive voice which leaves open the door for term as FLOTUS to continue into the future, if the sentence was re-written to accommodate the word "shown". Very clever little bit of wordplay if it's legit.
Then it would read: "I want to thank the millions of Americans who... showed the incredible impact..." which just sounds wrong. I don't think there is anything to this other than a simple grammatical error.
If we are to become nit-picky, it should state "I want to thank the millions of Americans who supported my husband and I over the past 4 years and have shown the incredible impact..."
Q doesn't expect us to rewrite sentences. Typos themselves give clues.
Also, just changing "shown" to "showed" works. Passive voice is frowned upon, grammatically. For her to be acknowledging she will no longer be FLOTUS, it should be "showed". Closes the door on the future. Clearly past tense.
The fact she used "shown" hints passive voice which leaves open the door for term as FLOTUS to continue into the future, if the sentence was re-written to accommodate the word "shown". Very clever little bit of wordplay if it's legit.
Then it would read: "I want to thank the millions of Americans who... showed the incredible impact..." which just sounds wrong. I don't think there is anything to this other than a simple grammatical error.
LOL doesn't matter if you think it "sounds wrong", it is grammatically proper English.
I was being polite. It is not grammtically correct.