The objective of this new tourist visa is to increase tourist spend (forget the guff about investment). They'll soon know if it's working, rather than giving a way for tourists with no money to live on the cheap.
There appears to be no requirement to show a balance in a Thai bank account. It's a hope and a prayer that so called digital nomads don't do all their online shopping outside of Thailand. It's going to fail due to bureaucracy, with all these applications citing obscure financial instruments and downright counterfeit financial certification. And that's before the Thai tax authorities want a take, and you get bogged down in taxation treaties, and whether the digital nomad has done business with a Thai entity.
No. The Thais, like most other countries, require financial surity, so that foreigners aren't a financial burden. Shares and property are worth zero until you sell. You can call it tunnel vision but your question was answered if you just bothered to research the Thai government announcements, instead of trying to game a system by being obtuse.
"Checking Account" is a Yankee version of a Current Account. Thailand only cares what money you have to hand, not where that money sits. Your original posting implied you have no financial assets to hand, and were trying to get into Thailand based on a future expectation of earnings. Again, the Thai government really want to know that there is no chance of you becoming of becoming destitute when living in their country. They don't want foreign beggers. You want to come to Thailand on the basis you earnt a million quid/whatever, but spaffed it up against a proverbial wall, and have no financial assets to speak of. What will you do in Thailand when you are sacked from your job/business collapses, and you have no reserve to live on? YOu have your knickers in a twist, when you haven't even read what the Thai government says, which is pretty clear:
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"Financial evidence: amount of no less than 500,000 THB, e.g. bank statements, sponsorship letter", Do you have 500,000 BHT? If you don't, forget DTV. Start saving money.
It's about proof that you can support yourself. Showing current income is no proof you can support yourself next week. It's the same principle as for short term visitors who might be asked for proof of funds.
Can all online shops be operated remotely. Depends what you are selling. Let's see if there is abuse of the system when suddenly everyone is drop shipping merch for their YouTube channels that have 5 subscribers.
Yes visa rules can change at any time. People with a 5 year LTR expecting another 5 years might find the Thai government has changed their mind/moved the goal posts.