Where did you get those figures? Are you saying that the employment in the Oil Patch is only 1/6 to 1/10 of what it was in 2008? Seems overly pessimistic.
COnsider two major factors: rig counts and tech changes.
Rig count here went from 218 (at the peak) to 24. Those remaining are walking rigs, and only do a complete 'tear down and reassembly' style move every 3 to 4 wells as opposed to the rigs in use in 2008, which had to be disassembled and reassembled every well. They walk, self-skid, or otherwise move from wellhead to wellhead on the drill pad now. (A three fourths reduction in rig moves means 3/4 of those jobs were gone before the price slump, and after that, the reduction in operating rigs to move was 85+%). This reduced demand for trucking in all but the liquids hauling (mostly production) part of the industry, as there were far fewer rigs to haul or to haul materials to. Consider, every drilling location directly employed 22 rig crew, 2 geologists, 2-4 company hands, 2 MWD personnel, 2 Directional drillers, 1 drilling fluids engineer, 4 solids control people. I won't count the truck drivers, safety personnel, mechanics, electricians, and other specialists who serviced more than one rig in that total, but their ranks were thinned considerably, too. Fewer drilling locations means less demand for site housing and the water/sewage services for that.
Pad drilling also cut down on the amount of earthwork versus single well per location drilling, and most of that earthwork is done on those well pads. Pipeline tie-ins are run to most of the pads. While there is more road to maintain, remove snow from, etc., it takes far fewer people to maintain it than to build it.
Fewer surveyors are needed, fewer landmen (leases are mostly all let), and their office staffs because pipeline routes, rights of way, road easements, and drilling/production locations are all mapped out and surveyed in.
The archaeological, raptor, and cultural material surveys have been conducted, as well as rare/endangered plant and animal surveys. Major road and highway construction projects are complete, what was a shortage of housing has been overbuilt, and now oilfield shop space (commercial) is vacant, so the crews doing everything from drywall, plumbing, electrical, roofing, etc. have packed up and left: their jobs are done.
Reductions in retail staff and hospitality staff and wages continue, and some businesses are starting to go belly up or close entirely. Larger oilfield service company shops have reduced hours, staff, and wages/benefits. Some have packed up entirely and consolidated with other offices or closed the branch. Only the production side continues to operate as it did.
Consider, too, that royalty checks have been reduced significantly, both by well aging (the first 80% BOPD production decline occurs in the first two years), and oil is bringing considerably less at the wellhead, and other sectors have felt the impact as well. (The other industry here is agriculture, and commodity price slumps in that sector mean that has failed to bolster the rest of the economy in the face of sliding oil prices and activity.)
I'd say the oil patch reduction here (with spinoffs) is likely pretty accurate.
I know that at 3AM in the nearest town, what was bumper to bumper traffic now is empty roads, and half of those vehicles are police on patrol.