USCIS will not stop paying its employees... Rather USCIS will find "cost savings" in failing to actually work in a reasonable time frame on the cases that are submitted for review.
How bad could this be? We don't know yet.
However USCIS is now quoting that an Employment Authorization Document that took 45-90 days to process prior to Trump for legally working in the US will now take approximately 28.5 MONTHS to 37 MONTHS to be produced.... and on October 2 you will even need to pay extra for this application....
This begs the question. Is US immigration even open for business if you need to wait three  years for a work card to begin working?
The Trump Administration's message here is clear. If you want to end all legal immigration to the US vote for Trump in 2020. The best and the brightest will move away, and the good jobs will follow them out of the US.
With four more years of Trump, US workers will begin immigrating elsewhere for jobs and opportunity as large corporations will see no need to staff in such an inhospitable, anti-international, and hateful climate.
Bottom line for now: we can expect delays in every facet of immigration processing, and if Trump is re-elected in November....