What you are referring to is history. Languages borrowing terms and lending them out back then is nothing something I have a problem with.
Today, the Internet, globalisation, etc. have decreased the number of languages in the world dramatically (last thing I heard is one language dies every two weeks) and there are approximately ~7000 languages alive.
While I know that most of these languages that are dying are spoken by very few (otherwise it wouldn't die). It is now more important than ever to keep each language unique.
What was great before (loanwords and such) may actually be a problem now.
First, as you say, these languages were spoken by very few people. I remember reading not long ago, the obituary of a Scottish dialect spoken in a single village. You can't really expect a language with such a small group of speakers surviving the advent of the automobile and the radio for very long. And these languages did not die by a thousand loanwords: the young folk didn't learn them, and the old folk who could speak eventually died.
There is also another factor at play here. "Proper" languages (that is, not dialects) have hundreds of years of written material behind them, and this is critical to ensure a language's survival.
Today, the Internet, globalisation, etc. have decreased the number of languages in the world dramatically (last thing I heard is one language dies every two weeks) and there are approximately ~7000 languages alive.
While I know that most of these languages that are dying are spoken by very few (otherwise it wouldn't die). It is now more important than ever to keep each language unique.
What was great before (loanwords and such) may actually be a problem now.