Tylore ji,
All subjects must evolve. The basis of Mathematics and newtonian motion across Space and Time cannot evolve, it just is. Our understanding can evolve but the hard sciences mentioned (not soft) reject theories that are illogical, doesn't go with Math or just break the concepts of space / time.
For example Astronomy which is a hard science (and the basis of Astrology) tells us at what relative positions from the Sun do outer planets appear in retrograde motion. So when Saturn is retrograde in 6th from Sun and at some point of time will be in the same Navamsa as Sun.
Question: Is Saturn direct in D9 now? If so, then the same Saturn is in two different motions and that invalidates the first Law of Motion itself! But if one still wants to accept the absurdity then next question - Is it combust in D9? If one accepts that absurdity as well, next question - What Samvatsar is running in D9 now? What Tithi? What Vaar? Just bulldoze the whole Panchang system
I would only spend time on Astrological magazines, journals especially new theories, methods, concepts sections after spending several years studying actual texts. Sure one can get into 'new revelations' but if they are breaking fundamental laws and postulates then they are not in the realm of Hindu Astrology anymore. This thread is in context of classical texts only.
About your statement of 'good results must have been obtained else the system would have died down' .... here is what is really going on. Most so called 'predictions' are just betting against the odds of life. And many of these bets are good bets statistically speaking.
E.g. if a 20 year old asks about marriage they are told - yes somewhere after 2024. When a 30 year old asks, now the prediction given is anytime in the next 12 months. So if ten people in late twenties ask this question and I give all of them a 1-2 year time frame then my hit rate will be anywhere between 60 to 100%. Don't need Astrology for that. Similarly I can tell ten unemployed people who are desperately looking that you will find a job in the next 3 to 9 months and again my hit rate will be impressive.
Astrologers are not working with zero information so they are able to make calculated guesses. They know the native's age, they can guess their socioeconomic status and their lives by looking at them, by the way the native talks and behaves. Additionally a good amount of info is given by the natives themselves or through questions asked by the Astrologer. Inject some Universal truths, feel good statements, incomplete sentences and you have a recipe for a nice cold reading. I am not saying its done purposefully, I am just saying that the basis of the statement that "D chart system should have died down if it was bad" is questionable.
In India all sorts of people are predicting ... some of them get a deity in them, some are looking at rice grains, others are looking at your clothes while some others smell it, some just look at the photo and what not ... all these are also "systems" that are alive because most of the practitioners are just betting against the odds of life. Outside India they take the form of Psychics, Tarot Card readers etc.
So please only discuss in context of classical texts, otherwise the thread gets diverted.