Turn based is superior for party based RPGs, as it allows for a much higher level of control of each member than is possible with real time... The only time its really done well in real time, is when it allows the player to pause at any moment (RTWP), giving them ample time to reissue orders based on the current game state.... but honestly you end up pausing so frequently in these games to try and optimize every action, that it may as well just be fully turn based. They key difference here, is that with RTWP you are manipulating the length of the turn and every character is acting simultaneously, as opposed to one after the other, so perhaps there is an argument to be had that there is enough difference between the systems that the later is worth keeping around.
The best turn based combat games for me, are the ones that also have a positional element to them - Tactics ogre, FF tactics,, Disgaea etc as having to consider your positioning in relation to both the enemy and your own troops adds a whole other layer of strategy on top. I suppose this depends entirely on how much you enjoy a good spatial puzzle though, which is something I've always been quite fond of. I describe these games as being 'chess like, but with more interesting capable pieces at your disposal.'
That said, even without the positional puzzle, the game can still have sufficient contemplative depth, as is evident in games like slay the spire, as it has a good good amount of meaningful decisions to make both turn to turn... and outside of battle with how you spec your character/deck.
The main issue I have with these games though, is that the AI is very stupid and predictable to the point where its very easily exploitable and then those exploits/strategy can be repeated in every battle, without much creative adaptation required of the player. This is usually overcome by the devs by setting up the combat scenarios to where you are outnumbered, and the battle becomes a puzzle of how to best make use of less resources at your disposable. Which admittedly is still enjoyable to figure out, but I do wish more effort was put into making the AI a more formidable opponent.
This is why if you actually want to experience this sort of tactical/strategic gameplay at its best, you should be looking into tabletop wargames/skirmish games, as a human opponent, even a lower skilled one, will provide a much more interesting challenge from battle to battle, with evolving strategy's and counter strategy' developing which are intellectually rewarding to explore. Yes its more expensive and time consuming of a hobby, with painting miniatures often required to make it more visually appealing, but boy is it worth it, as the games have substantially more depth with near infinite replayability before things become 'solved.' Take a look at the following if you want to delve into that realm... Malifuax, Infinity, Bushido, Warmachine, Guildball. Arena Rex, SAGA... just to name a few.
Why isn't turn based more popular? The primary reason is these type of games (at least the ones that are designed well) actually require a level of cognitive thinking, that to put it bluntly, the average person is pretty inept at.
I feel like there is actually a lot of room for innovation with this genre still, as there was a period of time - somewhere around the end of the PS2 era, where there really was hardly any good turn based games being made. Nearly everything became action based, sadly even series that were beloved for their turn based combat such as Final Fantasy. I wonder how FF might look today had they not abandoned the turn based systems and continued to evolve it. Instead of making it have more mass appeal by dumbing things down (but trying to to completely alienate its former player base) concocting this Frankenstein abomination of a hybrid of RT and TB we now see today, that doesn't really play to the strengths of either mode of play. You can make good turn based games on a tight budget, as pixel art is more than sufficient in these games, so hopefully the indie scene will start delivering more of these games for those that enjoy them. I have quite a few added to my steam Wishlist that look promising. Or perhaps the sales figures of games like Triangle strategy will be enough to encourage SquareEnix to devote more resources towards future development and other devs will see there is a market for them too.