A major difference between real science (as it was) and scientific research (as it is now) can be stated in the form that real scientists aimed to be as honest as possible, while scientific researchers do not allow their honesty to fall below a minimum level.
Real scientists were striving to be as honest as possible - constrained by the self-discipline, time and effort; other people's attention; the demands of bosses and referees and so on.
Modern scientific researchers strive to retain a core of essential truth in their communications - but in no sense do they try to be as honest as possible.
The appreciate that the system requires them to be dishonest, within limits, in order to get jobs, promotions, publications, funding (even in order to retain their status in situations where disagreement with the mainstream is regarded as not so much wrong as unethical).
Naturally, this means that real scientists were more honest that scientific researchers... but did this matter to the scientific process?
Was the difference significant?
Does it make any difference whether the average scientist is nowadays, say, 90 percent truthful when in the past the same person would have been 97 percent truthful?
Well maybe it does make a difference: maybe it makes all the difference in the world: the difference between science that works and science that does not work.
Maybe the combination of numerous persons work done with 97 percent honesty is still mostly honest, whereas the combinations of work done as 90 percent accuracy has dipped below the level at which it is useful - the proportion of noise to signal overwhelms the specific content?
Maybe, too, once humans beings abandon the iron law of truth, and instead of striving to be 100 percent honest, they begin to allow a certain 'minimum' proportion of dishonesty (with respect to 'inessentials' - merely as a means to the end of necessary career or institutional success)
- but maybe, once you begin using dishonesty expediently, there is no reason to stop at any particular point, no reason to keep the dishonesty minimal; and many reasons incrementally to ramp-up the proportion of expedient dishonesty until...
Yes, I think that's how real science works; why scientific research does not work.