Sometimes I stay in Vientiane for several months at a time. Extending a Lao visa inside the country costs US$2 per day plus a few minor fees, like the cost of the application form, plus a paper chase that includes coming back the next day to pick it up, and there is a limit to how many days you can extend. Exiting the country and coming back in is half the price and less hassle. It also allows for a monthly shopping trip to Tesco in Nong Khai.

Up until now the Thai entry permit was taken for granted when doing this, but I wonder if the new rules will shake this up.

There are no new rules that apply to your situation. You can continue to do that as before.