It was a rhetorical question, because there is no such thing as a "141 university." While a university may have a college or department for aviation, and that college or department may have a 141 authorization, it's not a 141 university, as there's no such thing. When the original poster talks of maintaining a low grade at a college, but then earning a higher grade at a "141 university," it is both misleading, and indicative of some ignorance on the subject.
This is significant in the context of the question because the original poster is talking about doing poorly with flight training, failing three practical tests for initial certification or ratings, and at the same time referring to doing well in flight school
While one could break down a transcript and attempt to explain away why one did well in one subject and poorly in another, most employers care about the overall GPA and aren't looking for excuses. None want to hear "I did okay here, not so okay there, really terrible there, and had a bit of an upswing here." Eyes glaze over long before then. Nobody wants to hear it, so unless they specifically ask, don't try. There is no mechanism in a resume or cover letter for such an explanation, and it won't be found in a job application.
The original poster stands about as much chance as anyone at attaining a position; it may take longer, or it may not, and as others have noted, it may never happen. A great many pilots don't work for the major airlines; some because they can't, some because they don't want to, and some just don't get a shot. That's life. Life doesn't end with the majors.
Someone disparaged ACMI carriers; there are ACMI captains earning several hundred thousand dollars a year. The company buys them a ticket to work and home. They ride a couple of times a month, have two weeks off, get put up in good hotels, fly internationally with lower stress, work in a relaxed environment, and enjoy considerable free time even when at work. They don't jump seat. They don't have to commute every two or three days. Life is good. Other ACMI pilots make less money, but still enjoy the same kind of life, and for some it's objectionable, for others it's the great unspoken secret and they love the job. For some it's comfortable. For some it's not, and for some, it's a stepping stone. It is what it is. There are a lot of jobs in aviation beside major airlines.
I've had jobs flying single engine airplanes making six figures with five or six months off a year, in a very relaxed job doing something I enjoyed...there are choices out there, some good, some better, some best avoided. Pick the poison that best suits and have a ball.
The original poster is talking about things that happened nearly two decades ago, and he or she has time on the job since, apparently with a good track record that should speak for itself. If the original poster had been busted for drug possession last year and had just slogged through school and failed a stack of checkrides, that might be a different matter. My counsel would be to get some solid work experience under his or her belt, let the record do the talking and soldier on. The original poster has already done all that, has the working experience, and is soldiering on. Were I to interview the subject, I'd be interested in whether they could do the job now, not in whether their skills were effective fifteen or twenty years ago. I don't care about fifteen or twenty years ago. I don't care about six or ten or twenty thousand hours in the logbook. Show me the last hour. Show me the next. I'll know most of what I need to know about a pilot before we ever get to a simulator, to an aircraft, and what I see in either one will only confirm it.
Certainly there are jobs which will never allow a blemished candidate to get past the front door. There are many others which will: the original poster is working now, and apparently displaying no difficulty in doing so. More PIC turbine time is warranted, continuing to gain experience is appropriate, but it shouldn't stop him or her from putting out resumes and applications, testing the waters, and seeing what comes back.
It's good and well to opine about it here, and to ask "do you think I'll make it?" It's better to put the applications out there and find out. All the conjecture in the world won't lead to a single job offer.
What anyone here says pales in the face of what an employer will offer or withhold. You can look at Mt. Everest all you want, even read the books and watch the movies. It won't get you one foot closer to the summit. The path to the top, however, is well known. The only way there is to get out and climb.