I absolutely understand why some people still favour the optical viewfinders of DSLRs, but I don't really get the logic of staying with DSLRs on the basis of having a few CF cards. Recent DSLRs such as my 5DMkiv had CF and SD - and the latter are crazy-cheap. Also people tend to replace slower cards with faster cards over a period of time.
I think the percentage of people who already have a DSLR, and choose to get another DSLR as an upgrade is pretty low. Upgraders want better specifications all round, and that means getting a MILC.
The vast majority of DSLR purchasers these days are probably novices looking for an affordable way into photography, and such folk are typically heavily influenced by advertising and influencers, who are almost exclusively promoting MILCS. So it surprises me that peer pressure from MILC users, and heavy promotion of MILCs by Canon, Nikon and Sony, hasn't led to a more rapid and severe collapse in demand for DSLRs.