Still see lots of boxcars around here. It just depends on where and when you look. On the BNSF main line near me, Ft Worth to Oklahoma City (ex-ATSF), there's a couple of mixed freights a day in both directions. Boxcars make up about 35% of the consists on those trains. The line is however over 50% intermodal due to the Alliance intermodal terminal about 20 miles south. There are also a lot of unit grain trains, full going south for export, and empty going north. On the BNSF mainline that was next door to where I worked for years, Dallas to Sherman TX (ex-SLSF), the percentage was near 75% mixed freights with about the same 35% boxcars. No intermodal on that branch at all, the only unit trains were gravel trains and covered hoppers of plastic pellets.
Meanwhile the UP main line from Sherman to Ft Worth (ex-MKT) that I occasionally railfan at, has a small number of mixed freights with a lesser percentage of boxcars. It's mostly grain, coal and automobiles.