Diagnosing a starter problem

Car has a really weak start for a while… Was on my way out to Advanced to get it run on their scanner to check the alt/batt/starter.

So, battery is good, alt is good.
When the car turns over, it just goes “click”
Single click, no more.

When I jump the solenoid by putting a screwdriver across it (skipping the ground), it goes clickclickclickclickclickclick.

Does this mean corroded ground issues? Or solenoid? or whole starter?

'04 Grand Am, if that matters any.
Delco starters aren’t known to go bad for a long time… But whatever… it is caked with goo.

starter was daaaaaayyyyaaadddd.
at least that’s what advanced said when they tested it on thier thinger.

$165 later…

not so bad, itll last another 10 years youre in good shape