Although I quit college myself after three moderately successful years (I did not “drop out”), and have had a successful career since then with no formal degree of any kind after my high school diploma (it’s been over 40 years now, so I guess I can claim “it has been a success” since I’m still employed at a technology / construction / engineering company on terms that I’m happy with) – I don’t normally recommend that course of action.
However, I’m tending to agree with @ragingloli here. Don’t look at the sunk costs (in terms of the money and time you have spent so far) as “investment” if they have no intrinsic value to you right now. In other words, if you were starting from scratch at this moment – having never had the college education that you now have – would you opt to begin again at your current institution and just tweak a few things to get to a better place within the same institution? Does your current education have any value to you aside from the time and money that you’ve already invested in it? Is there perceived value in continuing, beyond your belief that “you need a degree to compete”? If the answers to those questions are positive, then there may be value in putting your head down and finishing what you’ve started.
But do keep in mind that hiring managers are pretty well aware of the quality of educational institutions and do use their knowledge of those institutions to place a premium on (or discount the value of) the credentials that they issue. So it’s possible that your continued investment may be for naught if the institution is as worthless as you make it out to be.
Because you still don’t need a degree to compete. Education is essential; I will never deny that – and my three years of university did have value to me. But “credentials” are not as important as you may have been led to believe. I opted to forgo the diploma / credentials, took field work at low levels (no, I did not “start in the mailroom”, but I wasn’t far from it) and worked my way up.
Consider also that when you work for yourself and have your own business that you have absolute control over everyone who qualifies to work for you. And although I don’t know the interior design field – at all – it does seem to be the kind of industry where small contractors can compete for small jobs and make a go of it.