Yes it does...that's exactly what the quote says, let me quote the more important part:
"People who have access to a regular primary care physician are more likely than those who do not to receive recommended preventive services and timely care for medical conditions before they become more serious and more costly to treat. 1 Having a regular doctor is also associated with fewer preventable emergency department visits and fewer hospital admissions, 2"
Having a regular doctor, which is part of preventive care, quote "associated with fewer preventable emergency department visits"
First article you posted "Better still, we could aspire to provide preventive care with an eye toward individuals’ longer-term best health interests, hopefully keeping more cases out of the ER and hospital inpatient wards in the future. All sides should be able to agree that it’s time to double down on our support for these efforts."
Second article you posted "For instance, at a program in Akron, Ohio, profiled in the new report, physicians and others coordinate care for patients with Type 2 diabetes. It reduced the average cost of care by more than 10 percent, or $3,185 per year, largely by reducing pricey emergency-room visits.
And at Boston Children's Hospital, an asthma program that sends community health workers into patients' homes to reduce the environmental triggers of asthma has saved $1.46 in healthcare costs for every $1 invested. It has reduced asthma-related hospital admissions by 80 percent and asthma-related emergency department visits by 60 percent, reports the Trust."
Third article you posted "It is theoretically possible that giving people free preventive and primary care through Medicaid could lead to more diseases being caught early, and therefore less reliance on emergency rooms."
That article then claims it hasn't been tested, but it has in every Country with a national healthcare system.
The last article, the research, first sentence "Access to primary care could reduce use of more costly health care by uninsured individuals through prevention and early treatment."
With that, it not finding such a trend thus far would exactly match what I said.
Did you not read the articles?
This couldn't logically give Big Business access or control over your private life.