For the second. I suppose that assumes that a person that retired 6-24 months ago adjusted their expenses for inflation as things changed, and came to a new target investment amount to meet expenses at the 4% SWR. Basically negating the impact of past inflation. After one retires, the $ investment amount becomes fixed and responds solely to the market. If inflation continues tracking higher than normal then it will drive expenses higher. Unless they have fixed most of their costs (home, taxes, utilities, transport), they will be vulnerable.
The thing is that these two things (market returns and inflation) are not independent of each other.
The federal government spent a lot of money to get the country through the pandemic and the federal reserve created a bunch of new money to enable that spending. That extra money increased demand for both stocks (higher prices, e.g. outsized market returns) and consumer goods and services (higher prices, e.g. inflation).
Now the federal reserve is trying to slow inflation by putting the economy into a controlled recession. They may or may not succeed at getting us back down to 3%, but if they successfully engineer a recession demand will drop and inflation will be lower than it otherwise will be ... but so will stock market valuations.
If the federal reserve blinks first, get scared by how grim the economy looks, and go back to creating money instead of trying to pull money out of the system, inflation will go up even more, but the stock market will also have much better returns than it would in the world where the fed keeps trying to fight inflation by stalling out the economy.
A few down years of market returns coupled with higher than ~3% inflation will crush an early retiree.
I can understand how it feels that what, it it is not accurate. The 4% rule is ridiculously conservative even in the face of multiple down years and >3% inflation.
Consider the 1939 retiree. Three years in a row of down markets and inflation that rose from 0% at the time of retirement to 9.9% the year after and 9% the year after that. An early retiree however comes out okay. After 30 years their spend has grown almost 2.5x in nominal terms, but their portfolio is 60% larger than it was when they started
in inflation adjusted terms.
Or the 1973 retiree. Stock market was down 17% their first year and another 30% the next year. Their retirement coincided with the end of the cold standard, inflation was at 8.7% that year, 12.3% the year after that and didn't drop below 4% for the first eight years of their retirement. After 30 years their spending had grown to 4x what they were spending at the start. And, while their portfolio didn't do quite as well as the 1939 retiree they still have >98% of their starting portfolio in inflation adjusted terms.
These years may seem like random ones to talk about, but it's actually really hard to find periods where the stock market had significantly negative returns two years in a row AND had high inflation because, as discussed above, recessions tend to return demand and so reduce inflation.