Larger syndicates also have the problem that it's not always easy to wager as much money as they'd like on a small handful of leagues. So it becomes about how you can accumulate data and insight into a broader set of competitions.

A lot of the newer syndicates spread themselves quite thin afaik. They maybe don't have the contacts to get liquidity/early prices so they do lots of sports (Tennis and Cricket being two that appear to be growing...again, afaik).

I have heard that the largest syndicate has groups that only cover one football team. I have no idea whether this is true or how/where you get the liquidity to justify this.

This is the reality of how the bettors move the lines (ie odds on offer), large bets or a lot of small bets will move the line. In effect the final line at kickoff (or whatever) is kind of a distilled, crowd sourced expectation for the result of the match. The key is to identify advantageous lines when the major books publish them and place bets before the "public" moves the line.