Disclosures: this post is an anecdote about a Raleigh NC property for illustration purposes; the numbers presented are actual numbers from my Quickbooks report; the Rent-O-Meter price, T-Bill rates (in the links), taxes, insurance, and PM fees will change over time.
For the past many months, I don't know anyone with more than, say, $5,000 in idle cash who isn't using Treasury Direct to get 5%+ on idle money; pick your term - short (4 weeks) or longer (52 weeks).
Today, and a similar rate for the last several months, the yield (annualized) on a 4-week T-Bill is 5.22%. T-Bills are the safest investment in the world. I looked at the best-case scenario for a rental that I am selling (it's under contract) if a cash buyer bought it and placed it into service at a Rent-O-Meter average price, and the annual yield is 6.33%. That's not very compelling. The scenario: $295,000 purchase price (my list was $299,000), 100% occupancy, $1,900 monthly rent, with taxes ($1,856), insurance ($768), and property management (7%) the only expenses.
We had 64 showings in a little over two weeks. I asked the listing agent how many investors viewed the property, but she didn't have a clear answer. She speculated "a couple."
My point is that in a market where overall demand is unbelievably strong, the opportunity-cost numbers are not that strong for an all-cash, or any for that matter, acquisition relative to past history.
The answer to the OP question: Yes. I thought everyone bought with cash. LOL! And holding for 30 years? Maybe 27.5 is a better answer.
PS: the buyer of my company's property is an owner-occupant. They got a good deal; I wish them well.