This probably becomes more true when you've played enough that you are familiar with the routes and if you are playing with someone ornery enough to go out of their way to cut your route.
My wife tried this once, but it was because the two games prior, I drew the Vancouver to Montreal route (20 points, plus over 40 points in tracks), and I started building the north-most section of track in the third game. Her natural assumption was that I'd lucked into this route yet again, so she blocked the west-most segment. Luckily for me, that time, I'd drawn
Seatle to New York (exact same route, except for the last two tracks, and 22 points).
You can actually win by ignoring and mostly ignoring your routes and just going for longest train and long (high point) track segments. This ends up getting you points and often cutting off foes (accidentally or deliberately).
I may try this the next time I draw no attractive, high-point routes. The thing that can make this game so swingy is if you pick up a few overlapping high-point routes, it can be something like 20 - 50 free points for nothing more than a lucky draw, and you never see that coming until the end of the game.
I usually keep all 3 routes (sometimes even picking up more) and grabbing the small lines as quickly as possible. I also try to get the longest train, as the "free" 10 points is nice. I can't recall a game I've lost when I had the longest train and I've lost a game by less than the 10 points to the player who did. Taking a round about way also helps keep people from blocking you.
That seems counter-intuitive due to the low point-to-track ratio (and limited numbers of cars available). How do you win so often? Is it that you end the game well before other people have been able to complete all of their routes? I could see a "quick victory" approach working well by virtue of catching everyone else part way to victory and counting their routes against them.
Bonus points if they aren't paying attention and don't realize that you only have five segments left when they decide to draw new routes!