Real G.D.P. growth slowed to 2.8 percent year-on-year in the second quarter of 2015, down from 3.0 percent in the first quarter — and that includes the effects of a surge in tourism; discounting that, G.D.P. actually shrank. (The recent bombing of the Erawan Shrine in Bangkok will dampen foreign visits for a time.) Imports in capital goods have been falling for years, despite the state’s ever more generous incentives for foreign investors.

Thais are pouring idle cash into luxury condominiums and high-end shopping malls. Some $1.5 billion have been earmarked for the construction near Bangkok’s historic center of IconSiam, a shopping mall with retail space the size of 75 soccer fields. Touted as a symbol of “eternal prosperity,” this grand palace of commerce is also a monument to the junta’s misguided economic vision: the promise of consumption with too few consumers who have the income to fulfill it.

Gen. Prayuth seems finally to have realized these mistakes, and that the economy is his government’s Achilles’ heel. He sacked his economic team last month, replacing its head, Pridiyathorn Devakula, a former central bank governor from the conservative policy establishment, with Somkid Jatusripitak, the architect of many progressive social and economic policies when he was finance minister under Thaksin Shinawatra, the populist former prime minister and brother of Ms. Yingluck. Gen. Prayuth’s government also recently set up a national savings fund long in the making, which aims to help up to 30 million Thais without pensions.

These are welcome moves, and signs that the junta is breaking away from a style of economic management that until now one might charitably have called controlled inertia. But this is not enough. The only way to jolt Thailand out of its economic stagnation is to implement two measures that are sure to upset the Bangkok-based traditional elites: dramatically raise rural incomes (to spur domestic consumption) and aggressively devalue the baht (to boost exports).

The Thai state spent more than 72 percent of public funds in greater Bangkok, where only 17 percent of Thais lived, according to 2012 figures from the World Bank, the most recent data available. Mr. Somkid has already announced a $4 billion stimulus package for the rural economy, such as interest-free loans through the state-directed microfinance scheme. But these are essentially unconditional, short-term handouts that will at best cause a small and brief burst in consumption.