OpEx may be a little high, but he's including a lot in that number whereas most people break it out into separate line items that add up to a similar amount. He's including utilities, supplies, repairs, capex, etc.
So maybe a little high, but whoever said $3k is out of their friggin mind. I've had months with higher than $3k Opex on a single property. Heck, my bed bugs + broken fridge week I had a single week with more than $3k Opex, lol.
The reality is that, as STR has gotten popular and become another investment staple, there are people buying now for lots of reasons beyond cash flow, which makes it harder to cash flow.
A lot of people are buying as an inflation hedge, for appreciation, for debt paydown, for tax advantages, for their own use, etc. Heck I've heard quite a few people counting the mortgage paydown and tax advantages as part of a hybrid "cashflow" to justify it. And as others have mentioned, some are buying with cash and eliminating the mortgage, which lowers their CoC return but increases their cap rate.
Those of us that got in early enough to rake in $7500 bucks a month on a property not even accounting for the debt paydown, may have higher standards, but there are plenty of people just getting in that find a "free" monthly payment while the guests pay down the rent as worth it. Remember, for like 5 years there was a popular HGTV show called "vacation rentals for free" where the entire goal was to be net zero every month and cover your mortgage/expenses, and people ate it up.
There's a big gap in what cash flow investors investors want and what sellers want right now. Homes get listed at a price where gross revenue is 10% of the asking price. But savvy investors want a place where gross revenue is a minimum of 15% of the purchase price. But there are plenty of people willing to buy, for the reasons listed above, for a price where gross revenue is 10%.
That makes it harder for the cash flow investors, though many are still able to work around that, most notably by outperforming the revenue predictions (or prior revenue numbers) either via better management or via some kind of value add to the property.
It's still doable, just more difficult. It's not as easy as going on realtor.com and picking any random place in the Smokies now. You've got to find the right property or the right deal in order to cashflow, because you're going to be competing with a slew of buyers that don't really care that much about cashflow.