The composition of the Western tourists heading to Thailand has changed over the pas 10 years.
The change started in 1998. The value of the baht slumped in 3rd quarter 1997 and occupancy rates at Thai hotels fell. For the 97/98 winter season, a few Scandinavian tour operators got good rates from hotels in Hua Hin, which combined with the favorable exchange rate made Hua Hin tours a huge hit in Scandinavia. For the 1998 and 1999 seasons, mature Scandinavians flocked to Hua Hin while Thailand also became a hit in Germany and then in England.
The Scandinavian tour operators started offering more off-the-beaten-track destinations. An example is Khao Lak in Phang Nga. Over 2,000 Swedes were killed by there by the tsunami in December 2004, but which was a place of serene natural beauty when I first visited in 1999.
Back-packers are now a thing of the past. There are no longer anybody in their early twenties taking a semester or two off for a round-the-world or Australia-to-India low budget trip to explore themselves (i.e., to drink heavily, smoke weed, and have sex with other back-packers). Nowadays, there are a few low budget travelers in their late twenties or early thirties who take 2-3 months off to visit a few countries in Southeast Asia (and to drink heavily and/or have sex with other low budget travelers). However, even these low budget travelers can afford the occasional spa treatment, so they’re not real backpackers although they stick to the back-packer principle of minimizing interaction with the local people.
This principle is followed even more strictly by the package tour tourists. To them, sun & sea are commodities. Whether their package tour takes them to Ibiza, Mallorca or Thailand , is pretty irrelevant. The major tourist destinations in Thailand have thus also become "commoditized"; plastic places filled with plastic people.
The feeling of "original" Thailand almost vanished. It is still there, but one has to look for it.