It is very hard to diagnose an issue with fresh potatoes long distance, but I am guessing that since you were pleased with the taste and texture of Idaho® Russets for many years, that the issue is, your store now stocks primarily a Russet Norkotah variety potato from Idaho. This variety is an early harvest, allowing growers to harvest in August and September rather than wait till October. It typically is available in stores from October to March/April and is the second most purchased variety from Idaho (about 20%). The one you are probably looking for is the Russet Burbank, still over 50% of all production.

For an instant potato version of scalloped or mashed the companies have really made some improvements over the years. One favorite right now comes from Idahoan Foods, called steak house sides: http://idahoan.com/category/products/