This hyperspace tracking is brand new. The rebels/resistance would have never tried it in the past because they would always, correctly, assumed the empire/first order had their interdiction field up.
No. That doesn't track.
1. They get followed through hyperspace.
2. The first ship is running out of fuel
3A. You can let the ship die idly.
3B. You could try to kamikaze it.
There is no logic, period, that says you would ever just let the ship get shot to bits. You would try something, even if you thought there was only a low percentage chance it would work.
So, like everything else, the only explanation for not trying it earlier is "they didn't think of it" or "they were acting illogically"... both of those explanations are shit and amount to plot holes.
Again this is brand new technology. They have never encountered this set of circumstances before. They probably also assumed that they would have time to react if they saw someone moving into position to attempt that maneuver. Instead they were distracted by the escape pods and didn't notice what Holdo was doing until it was too late.
We don't know how long it takes to switch between hyperspace capabilities and their interdiction field. What if it takes 30 minutes? By the time they jumped to the resistance location they would be long gone without having to make another jump.
There are at least four implied premises in these paragraphs that are required to even get to a point where the First Order would have their interdiction field down AND the Resistance wouldn't try anything AND it would work when they did finally try it.
The first is that hyperspeed kamikaze at a ship actually works, and accepting that opens up a whole bunch of other issues (like the planet thing addressed below).
The second is that they have to follow them IMMEDIATELY for some reason. This doesn't really make sense given any description of what they're doing and the fact that they can't jump and then make a second jump because they're out of fuel.
The third is that even though we've never, ever seen it take more than a minute or two for a ship (large or small) to jump to hyperspace that'd somehow in this instance take them an impossibly long time to turn off their interdiction fields which, per your logic, they normally have up all the time. If it was a thing that interdiction fields took a long time to take down, then the Resistance would know from the very beginning that they didn't have them up because the First Order followed them immediately after their first jump. So logically this whole thing really falls apart... either they take a long time to take down and the Resistance would've immediately known after being quickly followed that they must've had them down OR they don't take a long time to take down. You have to pick one.
The fourth is that all of these ships that are out of the range of their lasers... so it wouldn't matter if they saw them turning around, cuz they can't reach them... wouldn't be instructed to test and see if these fields were down or try anything at all. No, their orders were "sit there and die" because... reasons.
So given all of that... where do we stand? The First Order knowingly went with a plan that would leave their ships open to a massive vulnerability for no reason... and then got lucky for a really long time while all the other pilots were totally cool dying as sitting ducks until Holdo finally was like "oh man you know what just dawned on me and no one else thought of!"? Sure.
And how did that go in the meeting with Snoke?
Hux: "So, like, we can track them through hyperspace so they can't run from us."
Snoke: "That's awesome!"
Hux: "But there's a catch... per Rian Johnson, they can hyperspeed kamikaze us... and, actually, it turns out they have always apparently been able to do this
despite it never happening or having been tried in any book or movie to this point and it ALSO turns out that basically we've just been having these super-important interdiction fields up to stop this from happening. Still with me? OK well the catch is we have to take these fields down in order to be able to follow them at a moment's notice."
Snoke: "Eh fuck it, let's roll the dice that no one will turn around and try to ram us. And you know what I feel like living EXTRA dangerously so I'll be on the lead ship following them. This is a totally rational decision to make, and after we know they're running out of fuel and couldn't possibly make two consecutive jumps let's STILL keep them down because #YOLO."
Snokes special destroyer was maybe 3x the size of a regular destroyer. That still makes it magnitudes smaller than a planet. Who knows if that would even be possible on something that big.
It's substantially bigger than that --
https://www.polygon.com/2017/9/1/16...-toy-supreme-leader-snoke-mega-star-destroyer -- it's triple the size of the Executor, and Executor was like 10x times the size of a normal star destroyer per Google.
And that's also irrelevant to the point... the point is that scientists say a 300 mile diameter asteroid traveling "slow" would have enough energy in its impact to basically wreck a planet. So, even something that is a mile across but traveling wayyyyyyyy faster would have as much energy and have the same effect.
Also reusability. You build one space station that can (in theory) destroy an unlimited number of planets vs having to construct a new massive hyperspace capable ship that you're simply going to kamikaze.
It'd obviously be way cheaper to build a whole fleet of bare-bones 1 mile diameter blob ships that only have a hyperdrive than a giant space station that's 80 miles in diameter AND took insane amounts of R&D to develop it's planet killing laser. But this point doesn't really matter, it's only tangentially related to this whole thing.
