People lost interest in her videos because she got from doing amazing videos like Ride, VG and BTD to doing :) videos, that simple really. I like this thread because if you don't live under a rock or in a cave sales matter since sales = money to produce albums and videos. Sales, charts or popularity don't affect my love for an artist but affects the artists that I love since producers, directors, makeup, payola, photography all need to get paid too
It's hard to compare the videos artistically but there is a simple way to see how popular they were/are.
She had only two proper videos this era which I think that are not suitable for the youtube spamming demographic: the use of Mahoney in the SoC video turned off a lot of people and WC video is a mess conceptually (they cut off a lot of scenes). We have practically two videos for WC, the audio version samples the proper video which was a bad move in my opinion (the audio version has more views than the full video version).
Here are some facts:
Born to Die: 160.276 views/day
VG (2 releases): 112.405 views/day
Blue Jeans: 107.000 views/day
National Anthem (3 releases): 56.684 views/day
WC (audio+full video): 175.292 views/day
WC (only full video): 97.561 views/day
SoC: 89.109 views/day
YB: 188.193 views/day
So this era is not that bad but it can be observed a significant drop in the number of views. I think that we have to take in consideration the lack of promotion and the music itself which is less appealing to that youtube spamming demographic (those disappointed that UV wasn't BTD 2.0).