Could you please shed light on the difference, if any, between "enter" vs. "break into" a market? Are they synonyms and interchangeable, or does the latter of the two imply more force?
My intuition is that enter is used more often after the event (‘They entered the market at a very good time') and that break into is used more often before the event (‘They’re trying to break into the market, but they’re not having a lot of luck’). This, however, would need to be tested by a detailed corpus search.
The relative difficulty in becoming a successful participant in a given market is often described in terms of barriers to entry.
If the barriers are fairly low (e.g., no significant capital investment, no market leader to overcome, no patent or trade secret obstacles), one can enter a market fairly easily.
If the barriers are high (a need to overcome the aforementioned challenges), one's efforts must be more aggressive and one needs to break into that market.
Notwithstanding the common coupling of breaking and entering, in market terms, the distinction has to do with the degree of difficulty of attainment.
Talking economically means that the latter is not forceful - instead, it symbolizes a breakthrough (and the two are interchangeable in this context). However, in common spoken English, "break into" usually represents force, in the sense of some sort of thieving. "Enter" a market in common spoken English represents walking into a market.
From my experience, I've heard them used mostly interchangeably. "Break" is the more colorful way of saying it - it comes with the connotation that entrance to the industry was difficult.