With flying less than 25K a year, you'll be so low on the upgrade list at carriers like AA or UA that you'll never clear (and may not be able to get on the list unless you're buying full fare coach). You also have to take into account they have a minimum spending amount, even for the lowest tier, and it might be a challenge to meet that if you're buying cheap tickets. AA, as an example, requires $3,000 in spend. Are you spending that much now? If not, you'll earn 5 miles per dollar spent pre-tax, which is apt not to be a lot of miles. I walked away from AA and I was at a tier that earned 11 miles per dollar spent pre-tax.

Being SFO based and buying cheap economy tickets, you should look at Alaska for domestic/Canada if they have the routes you need. They award 100% flight miles based on distance when flying Alaska metal and their lowest elite tier is at 20K, so you would see some benefits if you reached that lower threshold. They do have partnerships for Asia and Europe but accrual can be as low as zero (thinking of deep discount economy on Cathay) and more typically 25-50%. You would also get your Alaska elite 50% bonus after 20K (25K with partners).

There are different tiers when you mix partners, and with something like that the lowest tier is 25K but keep in mind most partners do not accrue at 100%, so you really need to look at the numbers before committing to status when mixing Alaska with partners (I did it in 2017 but for 2018 I'm using strictly Alaska).

As to award travel, Alaska does hit you with BA fuel surcharges when flying then, but on the other hand their business and first class awards to Australia are up to 40% less than what AA and UA charge. Compare the award charts. AA also charges those BA fuel surcharges, but you won't get hit on AA metal. UA does not impose fuel surcharges, but again keep in mind the road to accue miles on cheap fares with AA or UA will be long. Alaska does have some options non-BA that you could make work (Finnair and Cathay, for instance).

Alaska elite status: https://www.alaskaair.com/content/mileage-plan/membership-benefits?lid=nav:mileage-elite&int=AS_NAV_MP_EliteStatus_-prodID:MileagePlan
Alaska partners and accrual rates: https://www.alaskaair.com/content/mi...rline-partners