Austronesians arrived in SE Asia as early as 5,000yrs ago only?

It's likely SE Asians arrived much earlier than 5,000 years ago considering that the SE Asian Islands are closer to mainland Asia compared to Americas that was discovered and settled by Native American Indians somewhere between 15,000 to 25,000 yrs ago. 

Geneticist have put the date on Amerindian arrival in Americas as early as 15,000 yrs ago while there are substantial archaeological artifacts that have shown Amerindians arrived in America as early as 24,000 yrs. ago and there are several more artifacts that are above 15,000yrs ago also.  Amerindians also populated all corners of America and all the way down to Tierra del Fuego in South America as early as 15,000 yrs. ago. There are artifacts found in Brazil that was also dated at 22,000 plus yrs. ago. 

Migrating to the Bering Strait from Siberia to Alaska is much more difficult than migrating from mainland Asia to SE Asian Islands such as Indonesia and Philippines. Arctic Circle is extremely cold and dangerous for the first Americans to cross over to Alaska.  If they could migrate to Americas at this early date then that would also imply that it was also possible to migrate to SE Islands at an earlier date than 5,000 yrs. ago.

The scientist suggested that the Out of Taiwan theory is how SE Asians began to populate the SE Asian Islands as they sailed to Luzon Islands, Philippines and expanded either west to Indonesia or east to Micronesia and eventually Polynesia.  The problem is that these people would have had to use a sail ship in order to arrive to Luzon Islands, Philippines which is nearly 800 km or 490 something miles on rough sea. 

Makes more sense for me if SE Asians migrated from Malay Peninsula to Indonesia at a much earlier time date such as 10,000yrs ago or 20,000 plus yrs. ago as they followed the Australoid migration route that arrived in Indonesia, Philippines, Australia as early as 70,000yrs ago.  Around 10,000-20,000 yrs ago, several SE Asian Islands were not islands, instead they were one large landmass called Sundaland.  Sundaland was also close by Sahul that included Papua New Guinea and Australia which the Australoids eventually settled. Since the distance from Malaysian Peninsula to Sumatra Island in Indonesia is well within reach (36 miles or nearly 60 kms.), they only required a basic canoe to arrive to those islands.  Along with it, they only required a basic canoe to reach Mindanao and Palawan from Borneo Island.  Even Australoids who arrived in Australia only used basic canoes. If a culture required sailing ships to voyage the sea, then that implied that they had a basic canoe culture first for several thousands of years prior which is already enough to cross from Malay Peninsula to SE Asian Islands.

Also there are archaeological evidence that are dated earlier than 5,000yrs ago found in Indonesia such as Cibedug dated 9,000yrs. ago and Gunung Padang dated somewhere between 5,000 to 20,000 plus yrs. ago.  It could have been constructed by Australoids but it may have also been constructed by SE Asians.

There has definitely not been a substantial amount of research and genetic testing on mainland Southeast Asia as well as it's archipelagos and therefore scientist need to do an extensive amount of research and genetic testing here.