Are you certain your vote was counted and not lost? I vote in person because I know when I mail things they don't always get where I intended them to be (and especially when there is a deadline in place)
In my country, I can just bring the letter and put it in a special mailbox in the city hall in the weeks before the vote. I would trust the mail system, too, but that's beside the point.
In my case I complete my ballot ahead of time and drop it in a ballot box, which are distributed around my city. Then I get an email from my county clerk when my ballot has been counted.
I think the concern about things getting lost in the mail is reasonable, but is a separate issue; the mail system is supposed to be a highly trustworthy distribution system for sensitive documents. Hell, it's how you get your passport. That's why it's a state department (in the US, anyway) in the first place: it's an essential government function to have a communications channel with a given citizen.
I've been concerned about cuts made to the USPS leading up to the previous election, both because of the obvious impact on the USPS's ability to handle election materials, but also because of the potential impact on the arrival of other essential, time-sensitive documents. (Not essential, but my mother's anniversary card to myself and my partner fully bounced this year, after three weeks in transit. We only live 130 miles apart.)
My point is: threat models that center on the mail system somehow being unreliable are a valid concern, but missing the point.
Are you certain your vote was counted and not lost? I vote in person because I know when I mail things they don't always get where I intended them to be (and especially when there is a deadline in place)