I don't buy it. Give me an example, because the one's provided so far; Einstein's objections to QM and Victorian naturalists objections to Natural Selection, don't prove your point at all, quite the opposite, they indicate that scientists, when presented with a good theory, will give it due consideration. Einstein may have had his objections to QM, but even his own peers were giving away to it, because it explained observations very well.
If what you said was true, theories would come in fits, only when the old guys kicked it, but looking at the history of science, particularly over the last two centuries, that's not how it happens at all. The old guys, if they insist upon the old view, get sidelined long before they become worm food.
In the case of continental drift, the issue was that the theory had some serious issues at that point and thus those who objected to it did not object to it out of dogmatism, but rather because it was still a very shaky hypothesis. The same thing applies to string theory. It isn't dogmatism that leads the majority of the physics community to push it to the side and to seek for other potential theories of quantum gravity, but rather the fact that it is as of yet untestable, and therefore, no matter how well it might explain certain features of the Universe, remains essentially stunted by the inability as of yet to differentiate its predictions from a number of other theories (and, to be fair, none of the other theories, like loop quantum gravity or causal dynamical triangulation, are as of yet testable either).
This "old guard" argument is absolute nonsense. It's not as if the late Victorian and early 20th century biologists and naturalists had to all die off before the Modern Synthesis was seen as the grand unifying theory of evolutionary biology. It's utility was accepted very quickly, and didn't have to wait for the "old men" to die off.