I think that bitcoin will never become mainstream due to the nature of it. The only possibility I can see that it will get mainstream is via centralized parties, like easy-to-use exchanges managing the users coins.
What are the arguments that support bitcoin will go mainstream? Any argument I can find online is something non-related to bitcoin itself - For example, if the US government buys bitcoin, or Tesla accepts Dogecoin it isn't something that (in my opinion, at least) makes bitcoin more accessible for the normal, non-technical every day person.
I think bitcoin became a scam not by purpose. see, these days people on social media just tell you to buy it, because it's a currency and its price will go up. but what makes bitcoin a currency? its community? but most of its community just bought it as an investment, not as a currency - as an asset. it's like a pyramid scheme.
Bitcoin does bring some good things to the world, where free (as in freedom

) digital money is inaccessible, but to the western world, what it brings? gambling? crime? mostly. some will argue privacy, but what exactly is private about bitcoin?
It also grows exponentially in terms of energy and resources needed to operate it, which is a total waste.
Some will argue it's a "new kind of global currency". but again, most bitcoin users don't use it for daily transactions. you might say, how do I know that? simple - because all the data on the blockchain is completely public.
And it's overpriced.
Leave your comments.
Well it sounds like you don't know a lot about it. Most of your points seem to be strawmen to me, coming from a person who just found bitcoin and haven't looked into it.
How will it "go" to mainstream and what do you even mean by that? Bitcoin is currently 8th largest asset in the world surpassing marketcap of silver, so it is already mainstream. Or what are you expecting to happen? It's not going to replace a dollar if that's what you are after, but you can easily change it to goods via crypto debit cards for example.
I have been around for a long time and have heard all kinds of weird ideas how bitcoin is inter planetary money etc. I haven't never taken that kind of speak seriously, so i find it funny that newcomers are coming in this space, saying it's scam because some random dudes in the internet are saying outrageous things. And if you take their word seriously, and think that everyone buying bitcoin believes it would go up only, i understand why bitcoin would seem like a pyramid scam. Every holder knows that it's going to have a ath limit, and it's not just going up. Up only is a meme, not to be taken seriously.
Saying it's overvalued has been a thing that someone says about it during every bull run. No one knows where the top actually is and no one (except crazy people) even dreamed it going this high at the early years.
Privacy or pseudonymity hasn't been serious argument for a long time, least now when we have new upcoming regulations. I am not sure why some people still use that.