Sam might have a “little crush” on Spencer, but would that be enough for their to be a working romantic relationship?
I’m even going to ignore the age difference.
Does Spencer see Sam as a love interest instead of his little sister’s friend?
There is no evidence that strongly suggest he does. We don’t even know for sure Spencer considers Sam his friend and not just Carly’s friend. Even if Spencer considers Sam his friend as well there is no strong evidence he considers her more than that.
Even if Spencer saw Sam in a romantic way, and even if Sam’s little crush was still there, the relationship wouldn’t work for too long. I’m not denying that Spencer and Sam’s relationship is cute and entertaining, but wouldn’t transfer that well into a romantic one.
A big part of Spencer and Sam’s relationship is the fact that Spencer and Sam have funny interactions and goof off together. They certainly work as friends, but to think they’d last as a couple is to ignore a big aspect of Sam’s character- the wall she builds up.
Sam doesn’t normally open up to people easily, and usually needs a push to express her more tender feelings. Sam has never opened up to Spencer that way, and fell in love with the boy she could open up to, Freddie.
If Sam dated Spencer they’d probably have fun, but in the end of the day fun would be all that would be between them and their relationship would start to feel more like a friendship. People often goof off and have fun with a friend, doesn’t mean they have the kind of connection necessary for romance.