From the things I understand about there reasons of not being able to buy Bitcoin is actually the price so there is no strategy that will give them a lower rate of buying price of Bitcoin
It's their main barrier, as they consider Bitcoin price is too expensive, and even they think it will rise more, they hesitate to buy an expensive Bitcoin. If they can overcome this mental barrier and fear, they can start their investment but unfortunately, they mostly ignore "expensive" Bitcoin and spend money to buy "cheap" altcoins.
It's very unfortunately because altcoins are either low quality or scam and they will lose money with altcoins while if they believe in Bitcoin and invest in Bitcoin, they would have gotten very good profit.
Not only expensive but also Bitcoin is to volatile for them to handle. They hesitate to buy it because they have this fear that once they buy there's some instances that price would decline.
This is the reason why some people call it scam or so risky asset to buy. But if they just try to learn many things about Bitcoin and ignore those short term movement that happens for sure that they would never have those fear, but rather they continue to buy Bitcoin since they think that those pumps is good opportunity to accumulate.
But they would reach into that situation especially if they are open for improvements and constantly do a lot of research about Bitcoin.