Sexuality is a good thing, when used in accordance with God's will. What if it's not God's will for someone to marry at all?
If God gave a person a high libido / sex drive, but refused said person the gift of marriage, then according to 1 Corinthians 7:9, that would mean that God would have predestined said person to burn with desire because nowhere in the Bible can a Christian find any third alternative. 1 Corinthians 10:13 says that God doesn't let anyone be tempted beyond what they can bear.
The fact we have a desire doesn't create any entitlement to have that desire fulfilled.
It actually does, as long as the desire is not of a sinful nature and as long as you are a righteous person. Philippians 4:19 suggests that it is God's Will for all the needs of His children to be met. Psalm 84:11 says that "no good thing does He (God) withhold from those who walk uprightly. Marriage is a good thing according to Proverbs 18:22.
It is a straw man. You brought up a different topic, namely the desire for sexual immorality outside of marriage, while the thread was about why the Bible doesn't offer more detailed instructions on how to find a spouse. While sex is part of marriage, it is not the only component. Showing love for one another, praying together, spending time together, having someone to share your emotions and spend your time with in ways that offer you tenderness, cuddling, hugging, lifting each other emotionally and spiritually etc. All of these are aspects of marriage that the single people who desire to find a spouse are robbed of.
In a culture that places a hugely disproportionate focus on sex and sexuality we shouldn't be surprised that there's such a focus on having our own sexual desires fulfilled. And at a stroke sex becomes an act of taking rather than an act of giving, at which point once again it's all about me, me, me.
Well, seeing how Paul addressed this issues almost two millennia ago in the Middle Easte, it doesn't seem to be a cultural thing. It seems to be a pretty universal characteristic of humans.
We can look at all sorts of studies based on people who want something and can't have it. Did the study look at people who would like something and have accepted that they aren't going to have it? Is the problem being single or being discontented?
The problem is from both being single and discontented. The benefits of being in a relationship have been carefully analyzed and compared to the contentment offered by financial gain. While financial gain makes people happier
until it reaches a certain satiation point, being in a relationship does not. It is constant until (unless) the romantic love between the two partners disappears.
Going back to the loose comparison with material wealth, how many people who have riches most of us would consider vast still feel that they need more? Not a sense that they work because they like what they do or believe in their mission, I'm talking people who work to earn more money because they are afraid that their $100m fortune won't be enough. If you ask the average working person how much money he needs to be rich he'll probably give you an answer of a few million. If you ask someone with a net worth of $10m the same question he'll probably say $100m. And so the constant striving to get something that may be out of reach creates problems.
Your assumptions have actually been anticipated by science and proven wrong:
http://money.com/money/5157625/ideal-income-study/
I remember one guy I loosely knew some years ago. He was the head of a trading department for a major investment bank (Managing Director level). I wouldn't even like to think what he made in salary and bonuses. He kept working even though he was being treated for hypertension. I don't believe for a moment he needed the extra money, I truly believe that he could have retired and lived very nicely on what he had accumulated. Now it's academic because he died of a heart attack.
Workaholism and unhealthy obsessions with accumulating money are quite real, but again, that is irrelevant to the topic currently being discussed.
If your original premise was correct and it was so important for us all to be married you'd almost wonder why God didn't give a few pointers for people who struggle to find a partner in modern society. But then when society gets shallow to the point that the first focus is on physical attraction, and the less attractive and the disabled are constantly overlooked, maybe the problem is there rather than God not giving specific guidelines for how to perform certain tasks under every possible societal condition.
Society was quite shallow in Paul's time too, yet that didn't stop God from inspiring Paul to write letters to them to give them some basic instructions.
If an argument is based on little more than a guess whether something is a sin it doesn't sound like much of an argument. What if an unmarried person were to masturbate while thinking of nothing more erotic than their weekly grocery shopping?
That would be sex outside of marriage, so fornication.