When Socket AM4 debuted not only were motherboard and CPUs much more expensive than Socket AM3, but there were only a limited number of DDR4 modules which worked with them, often they were the more expensive variants, and those variants were not always easy to find. While those all hurt Socket AM4 no doubt, they didn't exactly stop people from buying them.
However, there is one important difference: Socket AM4 is -very- viable and will continue to be for many years to come. PCIe 4, multiple M.2 slots, 802,11ac and .ax WiFi on even mid-range models, none of those are going to prove insufficient for quite some time. Compare this to Socket AM3 where there was no PCIe 3.0 (outside of the Sabertooth 990FX Gen3/R2), SATA performance was abysmal, WiFi was scarce, and processing power was, to be kind, lacking.