I reject the notion that Phineas would ever conform to the conventional college-job-suburban house pipline. He is NOT conventional. Boy has fun at college for a WHILE, but it gets old quickly once he exhausts the resources he wants to use. Boy drops out and lives in a van for two years.
Boy starts a tiktok just as an easy way to share his location and what he's doing with his friends and family - no intros no outros no commentary and no tags. Boy accidentally gains a follower count in the hundreds of thousands because his toks are completely out of context and jump wildly between various entirely unrelated locations without reason. You never know where he'll show up next. He's sometimes seen at undetermined fairgrounds or at stranger's houses doing random upgrades/bizarre renovations.
He has no discernible income. It is unclear how he is affording to live like this. His van is twice as big on the inside at LEAST and the followers he has (who he never really address directly instead of rare replies to comments?) are frothing at the mouth. Is this one of those illusion gag accounts???? Is this whole thing a bit???
One video is a perspective of him climbing DOWN from the TOP of a very large conifer, only to see that there's a bear at the bottom watching him curiously. There's a shocked pause and silent laughing from Phineas behind the camera as he casually climbs back up again. "Ferb bro I *wheeze* I need a transport pleeease---" *cuts off*
The next video is of him and Ferb eating hamburgers on the top of the van. This rare Ferb sighting is especially strange because Ferb is not on social media, but he's not around 98% of the time so Phineas's followers have no idea where he comes from. The camera swings away the microsecond before Ferb uses the transporter to phase back to England. Followers only see a flash of light. The theorists go bananas.