This is correct, if you apply for a Non O at home before you leave -which is recommended- you can apply with proof of monthly income OR funds. My comment was just an answer to OP’s specific question.
If your embassy doesn’t offer to provide you a affidavit letter, you’ll need 800K baht in a thai bank account to apply for a 90 days Non O visa in Thailand and your first year extension of stay. After you’ve showed proof of twelve consecutive transactions over sea to your Thai bank you can use income (minimum 65K baht a month) to prove sufficient funds/income for your next extension of stay. Some immigrations accept a combination of funds/income 800K baht in total and some don’t. You’ll need to check this further with your local immigration.
You can apply for a six months multiple entries tourist visa at your embassy/consulate at home before you leave and travel in and out for almost nine months.
If you apply for a regular 60 days tourist visa you can purchase re-entry permits and travel in and out within the validity of your visa.
For 30 days visa exemption the restrictions is mentioned above.
Visa exemption gives you at date 30 days which you can extend with additional 30 days at your local immigration. If you apply for a 60 days tourist visa before you come, you can also do a 30 days extension at the immigration.
90 days Non O visa can as mentioned applies for at home or in Thailand on a visa exemption/tourist visa. The requirement is being above 50 years old. If you apply at home you can use both income or funds to meet the financial requirement. If you apply in Thailand you’ll need funds in your bank at date when you apply, unless your embassy offers to give you an affidavit letter to confirm your income. (The UK, US and AUS doesn’t). The financial requirements are income equal to 65K baht a month or funds equal to 800K baht.
Depends on where you apply, but for several embassies this is sufficient for issuing a regular tourist visa, or else they will ask for additional documentation as mentioned.
What we know is that Indian citizens are entitled to a 30 days visa exemption until 11th November at date. No one can tell if it’s going to be extended or if you’re back on 15 days Visa On Arrival and a regular 60 days tourist visa.
India is also among the new countries purposed for 60 days visa exemption in the new exemption scheme, but no one can tell for sure at date.