you are correct about the hashrate increasing which has made the network that much stronger but i don't know what "bug fix" you are talking about. there has been no bugs in bitcoin protocol to be fixed to make it stronger! however, there has been some bugs in some wallet applications and implementation like they always are which were fixed like always. i wouldn't say that made bitcoin stronger!

as for more people, i believe the real adoption is growing despite the price but there is another kind of adoption by the speculators and those who want to become rich over night and that was peaked by the end of 2018 and then fell down as price went down.