Let’s assume they know HOW, the answer is sometimes yes but sometimes no.
In the AAR contract (section 6j) it states that “If seller agrees in writing to correct items disapproved, Seller shall correct the items, complete any repairs in a workmanlike manner and deliver any paid receipts evidencing the corrections and repairs to Buyer 3 days or ____ before close of escrow.”
There are a few important additions to this information. If the Buyer has written into the contract (prior to inspections) that electrical, plumbing, etc., repairs must be completed by a licensed contractor, then the Seller has contractually agreed to hire licensed professionals and must do so. (Additionally, the general rule is a contractor’s license is required by statute for work that exceeds $1,000 in value)
Many homeowners have some experience with minor home repair, and a handyman is a sufficient professional to manage repairs for most items; including light switches, dimmer switches, etc., wherein they would competently complete a repair in a ‘workmanlike manner’. If the homeowner is competent to make repairs, they can go for it! So after the home inspection, the Buyer can not demand that the Seller use only licensed contractors to complete work. A Buyer can still make the request on the Buyers Inspection report, but the Seller is not obligated to hire licensed contractors, unless they agree to do so.
The Buyer can elect to have repairs completed by a specific date or go with the boilerplate language of 3 days before close of escrow. The final inspection is a Buyers opportunity to confirm repairs and to be sure home is in substantially the same condition as time of purchase. If repairs are not completed for some reason, although it is unfortunate, the Buyer will be obligated to close anyway. The Seller could provide a credit at closing to the Buyer for the cost of repair.
By closing the deal, the Buyer by no means is just out of luck on repairs if Seller failed to honor their written agreement. The remedy would be to close the deal, and then pursue the Seller in small claims court for damages. Although most breaches of contract can result in a termination of agreement, if a Buyer fails to close over incomplete repairs, the tables turn and the courts usually side with the Seller in that the harm to Seller by Buyers failure to close is typically greater than the harm to Buyer for usual cost of repairs. But at some point it is made right for the Buyer!