I've always worked like that. I started composing professionally in 1977. First musical in July. Then a second in October, but the second one was infringed on off-Broadway. Yes, I prevailed in that action.
But ever since I have been steadfast in my belief that my music is worth protecting, for one, but also that if someone wants to use it they do NOT own it. They lease it. I write most of my own contracts and have never had an agent of manager. Don't need 'em. lol.
It's also important to remember that I generally write what some might call "art" music. More broadly, I write predominantly for live performance or specialized genres, such as dance. theater, art installations, and - duh! - silent films. None of these folks are interested in collecting royalties from my work (unlike the vulture TV and big film distributers).
How important is that? It's effing critical, IMO. I have only one "work for hire" contract out there and those folks aren't interested in the publishers share. Their stuff gets on the TV machine about once a year. But everything else, including my catalogue with the Academy of Motion Pictures, is 100% mine.
Warner Bros. inadvertently received a minute of my music about 15 years ago and, unknowingly, placed it on a major DVD release. Had I not owned my publisher's share, I would have been out of luck in terms of recovering licensing. In the end it took about 6 months (which held up the DVD release) but the company supplying the material ended up paying dearly for that one minute of music. I won't tell you directly how much it cost them, but suffice it to say that at that rate, for 60 minutes of music, would be well over $1.5M. Damn, why didn't they steal more! lol
But there's another component to my madness: integrity. I'm not opposed to a buyout, but it has to be equitable (read: lucrative). None of this backend BS or "half to them, half to me." The royalties are for the publisher and the writer, not half to the distributer and half to "everybody else." I produce my work in my studio (or in a theater, soundstage, etc). It is MY product produced at MY expense. Beyond that, if anyone wants to use it they can lease it. Period.
I know... if you want to play with the "big boys" you gotta jump thru their hoops., at least if you want to establish yourself as a composer (don't even get me started on the stupid "apprentice composer" stuff that goes on in LA). Those are games I will not play. Maybe, if I got desperate, I'd consider that. Fortunately, I have never wanted for work since 1977, but am I blessed? Well, I'd have to believe in a god first, but no, I'm not blessed. I'm a stubborn Sicilian and will not have my work hijacked by what is essentially a corrupt system. If they want my music, they'll come to me - and they do. Also, don't play bars and weddings or anywhere people are eating except for popcorn in a theater.
And then there's the late night comedy gigs. A whole other world of fun.
Be well, FM. Wear you mask!
Any movie/scene examples that jump to mind? I know there are some hard-core film lovers in here 
) and then "La Adelita" (much better), in case you know them.