You really should compare itinerary to itinerary as both RCCL and Disney charge more for eastern vs western
Also as i stated some rooms are cheaper but not always the case
On RCCL the week of Jan 22 a verandah with 187 sq foot room and 50 sq foot balcony (237 total sq feet) is $2293.90
On DCL the week you showed the standard verandah is 204 sq feet with a 42 sq foot balcony (246 total sq feet) is 3006.70
On RCCL the same week a Jr Suite 287q feet and 80 sq ft balcony is $3595.90
On DCL the Deluxe family oceanview with verandah Cat 4e extended balcony 241 sq feet with 80 sq foot balcony is 3412.70
Don’t be fooled by the name of the RCCL room as a suite, it gets no extra perks or suite privileges.
Since we book Cat 4 when sailing Disney as we like the extra room it is cheaper for us than RCCL.
My point is everyone is complaining that Disney is so expensive compared to RCCL. I am just saying that is not always the case, Not every Category is more expensive, just most of them.
Also the argument that Harmony is newer ship and that means it will cost more can also be used for why Fantasy is more expensive, after all it is only 3 years old compared to 8 years for Oasis.
I picked week vs week because not all weeks are equal because of school breaks. It would be like comparing 4/15/17 sailings to 4/22/17 sailings and expecting them to be the same price, but one is Easter week and one isn't.
Actually, Royal has started allowing Jr Suite guests into Coastal Kitchen (which was delicious, btw). When we dined in CK, they also allowed us to take advantage of the happy hour than ran between 5pm and 8pm. I don't know if this is going to continue or not, and it's only on Oasis and Quantum class which have CK.
Oasis only first sailed in December 2009, so she is only 2yr 3m older than the Fantasy. Allure is only 1yr 3mo older than the Fantasy. Harmony will be four years younger than the Fantasy and is still attracting inaugural ship pricing.
I just pulled up prices for Allure's April 16th 2017 Western sailing (since Allure is closest in age to the Fantasy). A Jr Suite is $4026.68. A Cat 4D verandah (as 4E only has the large balcony), is $5993.16 on the Fantasy's April 15th 2017 Western sailing. That IS a huge difference. 99% of the time, Royal will be cheaper. And like you said, off season Jr Suites compares to cat 4s might be the only exception.