From an upcoming senior in college:
IMO, I think it all depends on the person, but I think motivation is important regardless of graduating from HS or college. However, I’ve heard stories of people who lost all care because they already got accepted or found a good paying job right out of college.
Having gone through many many senior years at both college and high school, I can attest to the fact that the transition from teen ages to young adult is real. Tremendous maturity differences. Not much talk of senioritus in college.
No senioritis in college: you’re keenly aware this is your last semester without full adult responsibilities, after that ‘screwing up’ won’t mean a bad grade but losing your job or causing real damage, and your last chance at improving that GPA, it’s Also your last semester to hang out with friends who’ll be gone anywhere in the county, last semester to lead that charity project or the college paper or that club that matters to you, last semester to take that class you always wanted to take, pretty much the end of an era and the beginning of a new one - and, unlike high school to college, which meant more freedom and fewer restrictions, the opposite is true for what’s awaiting you. So, no senioritis, quite the opposite: living intensely these last months.
Actually senioritis can be handling a lot of pressure really badly. When you’re 17 you’re expected to know what you want to do, be excited to dive into college, etc, and a lot of kids just aren’t ready for that at all. That’s why for some kids you find a lot of Slow the Roll, hang out, and avoid the big decisions and transitions as long as possible. They aren’t savoring as much as avoiding.
I know for me senioritis in college was very real and it was driven by not having a good job lined up, not knowing where I wanted to go, and really not feeling ready to engage with adult life. From the outside it may have looked a lot like kicking back and enjoying the good life but it was anything but. (You should have seen my bar bills.) Eventually I got off the couch, got a job and made my way forward, but not until well after the summer after graduation was over. YMMV.