Is there a reason two interstellar objects were found in the solar system in such a short period of time? ʻOumuamua was discovered on October 19, 2017, and 2I/Borisov was discovered on August 30, 2019.  Has something changed about observation techniques or equipment that made it possible to find these objects in less than two years?

I find it hard to believe that there has been no interstellar objects passing through the inner solar system in the past ten or twenty years, then suddently these two did, quite close in time. 

I recognize it is incredibly hard to find such small, dark objects moving so fast, especially if they are outside of the ecliptic, and there be many more passing through that just haven't been discovered. Should this be chalked up to pure luck?
The biggest contributor to these two observations happening so close to each other is capability and interest.

Our ability to observe such objects is ever increasing.
Once we saw one, our interest increased and we looked harder ie. lots more funding for the necessary observations to be made that would identify such objects.
We saw the next one soon after.

There is unlikely to be anything special here, just the politics of scientific funding. 

It may be that these were two objects that coincidentally passed through the solar system at nearly the same time, but we are going to need to make many more observations of such events before making such a determination.