If you really want to try
DCL, there may be some ways to get it closer in price. Different itineraries, different times of the year (off peak), wait to book on the first day they are released, book through Costco and get an 8% refund from them (in the form of Costco credit), etc.
But at the end of the day, if the cruise you have your heart set on is 3X more on DCL, my guess is that you will not find the difference worth it. Mostly because it is the price you are focused on (which is fine). Most of the advantages to DCL can't be given a monetary value, and those that can are maybe 20% better, or 50% better, not 200% better.
Its rather like comparing WDW to a Six Flags theme park. Six flags is a great Amusement park with Roller Coasters and kids areas and shows and activities, but is it no Disney World. It also costs half as much per day, or less. Personally, I like them both, depending on my mood or my budget. Six Flags is a nice trip. WDW is an Amazing trip, but at a VERY high Premium. Some people would only go to one or the other. DCL is rather like that also.
At the end of the day, you have to do what you feel comfortable with, but if you are focused on the price tag, I suspect you will spend much of the cruise thinking of the dollars, and not the magic. If you think that is the case, try the other line. If on the other hand, the DCL price is something you can handle for a vacation, then go and have fun and never mind what that other line costs. You can always try them some other time.
Best of luck!