Single-minded = strength of mind.
As for no more miracles?
Hi, my name is Lynn. The Lord has healed me of chronic UTI, a bee sting, (where I had a terrible reaction to a bee sting as a child and know bee and ant allergies just get worse. They don't disappear), and fire ant bites.
My husband has been healed of Hepatitis C, long before that new drug came out, cancer on the kidney, and a heart attack so bad, the original doctors come running when they hear he's back to visit, because they cannot believe he is alive. (Dead man walking.) Even his medical file makes new doctors stop what they're reading to look at him, because he shouldn't be sitting there.
And absolutely none of that was done with single-mindedness. I distinctly remember telling God "your will, not my will, but not going to lie. I really want him back. So, if you won't give me him back, help me get through that too." Not very single-minded of me.
And I distinctly remember expressions of other people's faces, and feeling that same expression on my face, when someone was healed. The word is "shocked." Sure there was prayer, but every time God heals, there was always great shock that he actually did heal, because, let's face it. He doesn't usually heal.
Still miracles happening. Never was about the singled-mindedness of man. Man doesn't do single-mindedness too well. (Not sure it's even possible to do.) Always the Lord, and he's still doing it.
I suspect less miracles now than before simply because miracles would often used to get the people's attention before preaching the gospel. Less now, because most of the world knows the gospel, so the only thing we're doing is seed sprinkling in hopes God uses it for his effectual calling.
Still, sometimes real people need real healing, so praying is good. I can't say the UTI was going to kill me, but it was miserable for years. That first bee sting caused my entire leg to swell and become useless for three weeks. The first ant bite gave me hives all over my body. The second one was going to be worse, and I really didn't like the first one.
Hep C would have killed hubby by now. That cyst of cancer would have started taking over his kidney by now. I saw him the day of his heart attack. He was a goner. So the Lord extended his stay on this planet and stopped me from feeling miserable for 3 weeks to 37 years.
I don't know why he doesn't heal everyone. I know it's fair, because what we deserve is far worse. But I will not say there are no miracles because of the content of man's mind. I know there are miracles by the content of God's character.