Yes.. people can deny it.
The best strategy is DCA, and buying the dip is a good supplement to DCA.. but it is not as good as DCA... So when in doubt and you are not sure about what strategy to follow, DCA is the best Hands down.
The best way to convince people about DCA, especially in Bitcoin, is to have them ask their grandfather how much they purchased their first house, or their first car. Then let them imagine that they are grandparents with grandchildren asking them how much they purchased their first Bitcoins.
I doubt that is the best way of thinking about how to tailorize bitcoin to individual circumstances and the particular opportunities that present themselves (especially to normies) through something like bitcoin.
I have outlined several times that people do not tend to have lump sums of cash that they are either hanging onto or that they would like to go into debt or that they would like to hang onto cash and try to time opportunities to enter into whatever investment. Of course, a house is a bit of a different investment because of living in it, but it is still subject to the bullshit over-skewing of the importance of debt.. so currently there are all kinds of people and institutions hoarding housing because they are afraid to keep their value in cash or some other assets that are questionable in their fundamentals.
So, even though history can sometimes inform us about what we might want to do now, or what kinds of risks that we might want to take, one of the great things about something like bitcoin is that any of us (even the most normie of normies) can get into it with very little capital and we can customize our strategies and do not even have to qualify to become eligible to get into it.. We just have to take some actions to set up accounts or get some contacts with folks to buy directly.. sure there can sometimes be some elitism in terms of those with banks have more options, but we see systems developing in very poor locations (including El Salvador) that seem to be increasing the developments of options in which even the poorest of the poor can get into bitcoin without having very many fees and then they can take advantage of even smaller incremental investments if that might be all their budget (and situation) may be able to tolerate.