Five years ago, when it was first released, Modern Masters 2013 felt like a masterstroke.
Modern was itself only about two years old, and accessibility was already becoming an issue. The format's top staple, Tarmogoyf, had just broken the $100 barrier, and nobody believed that WotC would ever reprint that card in a Standard-legal set-it was just too powerful for the format. But here was a brand new expansion that promised to act as a release valve for expensive card prices, and it came complete with an excellent Draft format and its own signature event: the very first Grand Prix Las Vegas.
Modern Masters 2013 helped lower prices for a couple of months, but the excitement surrounding the set caused so much additional demand for Modern cards that its effect on the market was relatively short-lived. The format was growing in leaps and bounds back then, and hype was high by the time Modern Masters 2015 rolled around. Some people grumbled about the price increase from $6.99/pack to $9.99/pack, but most stores had been charging about $10/pack for Modern Masters anyway (the original print run was very small) and lots of folks were just grateful that they didn't have to wait in line to buy packs this time. Modern Masters 2015 was also a success, it also came attached to an excellent Grand Prix Las Vegas, and we couldn't wait for the next Masters set to drop in 2017.