I have taken this route. Never married and no kids. I am almost 40 and have been mongering since my early 20s. It is a really interesting question, and I will share my perspective on it. When you are in your 20s and early 30s there is a lot of pressure to form relationships that lead to marriage. There is the social aspect of it (all your friends getting married), family pressure (why aren't you dating, why aren't you married), financial pressure (hard to buy a home on one income in your 20s), etc. Most guys that can are going to get married, it's just that simple. Almost all women want kids, there are exceptions, but by age 28-32 most women want to have had a child. So by age 34/35 most guys will have been married and have at least 1 kid. It really is the path of least resistance. Being single from age 20-35 is hard, especially if you aren't good at attracting women and getting laid, which a lot of guys struggle with. Now, past age 35 things start to change a bit and mongering becomes an easier lifestyle to maintain. The big reason for this is money. To monger consistently requires a good income, in many cases a really good income. $200 is becoming the going rate at AMPs and if you go twice a week for 50 weeks a year that is $20K. It could be more or it could be less but to do it responsibly (not spending an outsized % of income on it) and consistently (going once or twice a month is hardly worth it) you have to earn a good living. For most guys this becomes more manageable as they progress in their careers. The biggest benefit of the "mongering lifestyle" is you can have really good sex with lots of women for $15k-$25k a year and the freedom and independence others have noted. There are drawbacks to the lifestyle, 1.) it impacts social and family interactions. People wonder what your "deal" is and you can't tell most people. 2.) Being single and living alone isn't for everyone, there is a lot of quiet time and boredom.
If I had to guess, 85%+ of mongers are married or in a committed relationship. "Just mongering" isn't going to work for most guys. But if you are the type of person that is ok being alone, really value your independence, and make good money, it can work. Additionally, if you earn a high income you will probably be better off financially in the long-term not getting married and having kids. Just my 2 cents.