The first time, I left D&D during the shift from 3.X to 4th edition. I stayed with Pathfinder for one campaign before realizing that I really WAS burned out on the 3.X/PF style of crunch. I gamed sporadically between the release of Pathfinder 1e and the release of D&D 5e. There were a lot of real-life issues that prevented me from gaming as much as I would have liked.
I always played other games in between D&D campaigns, mostly Star Wars (d6, then FFG), as well as a smattering of other games. I ran a lot of Paranoia 2nd Edition, Ghostbusters, and Star Wars d6 at conventions during this time as well.
I came back to D&D with the release of 5th edition, and while I play or run other games in between campaigns, I never "left" D&D during 5th edition's life cycle until... last winter, during the OGL debacle and the MtG Pinkerton incident. I'd been uneasy with some of WotC's business practices for a while and was dissatisfied with their hardcover adventures, in general, though I still enjoyed 5e. But, after the OGL debacle, I decided that I could no longer support WotC and while I could play D&D for YEARS without giving another penny to WotC/Hasbro, I and my group voted to switch to a different system: Pathfinder 2nd edition.
The choice of system to replace 5e mostly came about because we still play remotely and Pathfinder 2e largely fully supports Foundry VTT at no additional charge. As I had recently lost my job of 21 years, this low monetary barrier to online play appealed to me since I had been using Foundry already since around 2021.
I can run games that feel very much like what I ran with D&D using Pathfinder 2e, though I'm not entirely convinced that I enjoy the complexity of the system. I do find it easier to prep for than 5e, because the math seems to be tighter and more consistent. I could almost guarantee that my players' D&D characters would hit several levels about their weight, right up until I used a monster that didn't let them do that, and often, that would only show itself in actual game play.
But, as I get older, I find less to like in complex rules systems and tend to enjoy more rules light system better instead. Perhaps, this one campaign of Pathfinder 2e will be the only one and we'll choose to change systems for our fantasy game again. Perhaps, we'll return to D&D using just what I already own, with the understanding that neither I nor my wife will be spending any money on any WotC/Hasbro products for it. I had actually begun prep to run The Wild Beyond the Witchlight, including purchasing most of the minis for it, when it became clear we were NOT going to resume face-to-face play in the foreseeable future (several of my players have health issues which make it challenging in this post-COVID world to see gaming as an acceptable risk). Sure, I could run it online, but I can't use all those minis online.
I also feel very constrained by what I have available in Foundry. My group doesn't do well with theater of the mind, and I don't particularly care for the amount of data entry involved with systems that don't enjoy full support, so I always have to balance the workload. I also have to juggle the fact that my group is a mix of player styles that run from "Just let me kick down doors, stab some baddies, and roll some dice" to "Let's roleplay a shopping trip!" and several stops in between, so games with heavy player-based narrative controls don't work for enough of my group (and the fact that you don't actually need codified rules for straight role-playing) that I tend to shy away from them. I've been playing with largely the same folks for over a decade and I like for us all to agree when it comes to choosing a game for long-term play.
I think I could be happy using Savage Worlds instead of D&D, if we don't stick with PF2. But, there would have to be some go-to system on my shelf for fantasy games, and after 40 years of gaming, I know what I like and don't like about a lot of the options out there, and while I do find games like DCC (or other OSR options) fun occasionally, I don't like them enough to run extended campaigns. I LIKE D&D 5e, for the most part, and my choice to not play it is my boycott of WotC/Hasbro. There's really little else I can do to show my displeasure with the way they maintain their stewardship of the game. I'm just one person with one gaming group and no platform, so nothing I do will actually affect them, and can I only satisfiy my own conscience.