Well considering how many people on here think you are operating a resort in Thailand (but you're not), that's probably where the issue came up. The embassy review person probably thought the same thing. I would resubmit and leave out all the comments about tourism and outline how your business is located outside of Thailand and just tell them you will be working remotely. What you do on your time in country is your business. You also should be filing under remote worker not under the "soft" version of DTV.
Constanyly having to get an IDP every time you come to Thailand.. Just get a thai DL and you are good for 2 years and it costs like 500 baht. I couldn't deal with the nonsense of going to AAA or whatever agency issues them in your country every time it expires. Its one more thing to carry. With a Thai DL I also dont need my passport to get on a domestic flight. One card and done.
If they are "wealthy people" they can hire one of the better law firms to do their visa work for them. Real simple. Then if they are not really wealthy they can complain and go somewhere else.
Get your visa back in the states after you renew your passport. The consulates/embassy in the US is alot more lenient especially when it comes to showing money in the bank. You don't need to show 3, 6 , or 12 months of balance. For now I would just return on visa on arrival or pay for a tourist visa depending on how long you have been out of the country.