For you younger guys,
....Once upon a time, in a time sadly now a long time ago, you could order a vehicle optioned just about any way you wanted it...
"You want a K1500, Z71, Extended Cab, longbed, w/ F44 Suspension-14 bolt SF, GT4/3:73.1, G80/Posi, 5 speed manual, LO5 350, hydro boost brakes, no-A/C, manual windows, manual locks, Leather buckets, vinyl floor cover (no carpet), roof marker lights, and radio delete?
Sure Thing Pal... that'll be $XXXXX.xx"
Forced Option Groups/ Trim Packages pretty much became a mandatory thing in the later half of the 90's. It used to be that you chose your regular production options (RPO), if you ordered a new car/truck. There were some forced options, but they were usually tied to weight/towing/cooling/safety/powertrain combos. You could order as few, or as many options as you wanted. Option Groups/Trim Packages were how you could save money or add looks/performance. When GM bundled options together, it made assembly easier for line workers, saved time on the harness assembly, and generally saved GM production time/costs... They passed a small portion of the savings along to the dealer, or smart buyer. Dealers screwed a lot of people who ordered new vehicles by charging regular price for each option, then pocketed the difference for given option groups. Someone at GM realized they could save a lot more time and money by eliminating many of the individual option choices, with "Mandatory Option Groups" and later, "Trim Packages".