Good observation and question. My statement purposely deserved this.
Firstly, and primarily, my simplest answer in overview without all the Scripture actually posted at this point (hopefully you'll recognize where I'm drawing from) is:
- The Word of God and Spirit of God remain active in the world. Proclaimers are being sent and the Spirit is convicting/convincing. And since they are both inextricably interrelated, then they each and both have the power to do what they are doing. And the foolishness of God is wiser than men, and the weakness of God is stronger than men. I think He laughs in derision against any man who thinks otherwise.
- Precisely how God gets through to men I have some thoughts on (see below) but I remain open to discussion from Scripture.
From there, I don't think God submits to the boxes men make for Him and He has many ways to accomplish His will:
- Rom3 seems all inclusive but it is being written by someone who is not or no longer is included, and the Scriptures Paul draws from distinctly identify the fools/wicked who say there is no God while also identifying God's people, so not all are fools who say there is no God. I see no way of going down through history in the Bible and coming up with all men being the God rejecters Paul seems to speak of. Generally speaking, sure, but not in the absolute sense even though at times in history things were worse than at other times. Some men do not reject the knowledge of God that He has made clear in all men.
- Acts2:37 I think this is simply what it says it is and it's not the transition you may think it is if you see Rom3 differently than I just explained. Acts 2 is men who believed God existed and who were expecting Messiah and transitioned into belief that Jesus is Messiah based upon work the resurrected Messiah / the Spirit was doing among them along with some of their countrymen sent by God to proclaim the Gospel to them.
- The Gentiles:
- Men have consciences and that conscience is God created and God given and the work (singular) of God's law is done in men to varying degrees. Man's conscience can be extremely strong in some if not many. And orientation to conscience however strong or weak, if the standards are from God's standards, then the orientation is to righteousness and one of the things the Spirit is convicting of is righteousness which is correlated by Christ to belief in Hm.
- FWIW, I actually think this orientation is much more important Biblically than many seem to care to discuss.
- Life experience & desires coupled with an awareness of God's existence can and do combine and result in knowing there is something better for us, and coming to the point where we know it is not found in the things in this world. As some are discussing in this thread, many men are seeking meaning elsewhere. It's not a rare phenomenon.
- Along with man's conscience, his reasoning abilities though infected as his conscience is, are still functional to the degree God is perfectly and intimately aware of. The hardening of the heart is a process based in continuing rejection of God and I don't see it as automatic for all men. I've read from and spoken to men who through reasoning came to faith in Christ. Please notice I said "came to..." This is not meant to be isolated from my "Firstly" statement above. None of these points are to be isolated from what God is doing to make His Son clear to men.
- And so on... Always much to discuss.