Also consider that sets are designed with price points in mind (i.e. a wave of sets from a theme will have a distribution of prices). The new Ender Dragon set was mandated to be at a smaller price point, and does not reflect the choice of a LEGO designer. Therefore, it is not a fair comparison. I think looking at the evolution of Star Wars snowspeeders (as mentioned above) is a better metric to measure change in quality and price.
LEGO has made seven minifigure-compatible snowspeeders since 1999.Three of which include just a snowspeeder with no large side builds.
1999: 7130 Snowspeeder
215 pcs, $20.00 USD
2004: 4500 Rebel Snowspeeder
214 pcs, $20.00 USD
2014: 75049 Snowspeeder
279 pcs, $29.99 USD
While LEGO snowspeeders have not changed drastically over the years, each update to the design brings increased accuracy to the movie version. This is due to the innovation of newer, smaller, and more versatile LEGO elements. Therefore, more parts are used to create the model.
A large price increase occurs between 2004 and 2014. While the base snowspeeder is roughly the same size in each set, the newer version has greater accuracy with newer parts. Also consider the 2014 set has four minifigures--two rebels and two snowtroopers--while the 2004 set only only two rebels. Additionally, the 2014 set has a more useful side build (a turret instead of a radar dish). These factors give the set better playability. While the price has increased, the quality and usefulness of the contents of the set as a whole has also increased.
If we compared the two UCS Snowspeeder models (10129 from 2003 and 75144 from 2017), the newer set has 246 more pieces and is $70.00 USD more expensive. However, the objective quality of 75144 is a massive increase over 10129, especially in the assembly, which uses more sophisticated techniques to achieve better looks.