My wife was born in Washington State in 1954. She resided in America for about one year and came to Canada once her father completed his university studies..
One year in America, 61 years in Canada.
She retains US citizenship, it is difficult to cancel, and has a US passport as required for travel into and out of America.
She does not seem to be allowed to vote. She is more recently required to file largely redundant US income tax reports, despite the US/Canadian tax treaty that worked for decades.
Is she in any way eligible for any US Social Security or other benefits? She seems to have only obligations and no benefits
arising from her residual US citizenship. Thank you.
US citizenship in and of itself does not entitle a person to Social Security benefits. She must either have worked in the US, or qualify as an auxiliary (e.g. spouse, child) or survivor on the account of someone who did.
The US does have a totalization agreement with Canada, so it's possible that your wife could qualify for a totalization benefit if she paid US Social Security taxes for at least the equivalent of a year and a half. This would have to be in addition to a sufficient amount of work under Canada's system.
Otherwise, unless you worked and earned enough to qualify for US Social Security benefits, I know of nothing she'd be eligible for.