Messaging is always a weak point of Democrats and also bragging about their accomplishments and ideas has always been their problem, especially when they are trying to break through the outright right wing lies and propaganda of talk radio and Fox news and also the constant "both sides the same"ism game the "Liberal Media" likes to play. So, this is where I would agree that unfortunately Democrats drop the ball. Obama in my opinion had a big problem as president doing this. Lack of advocating and pushing out there what you've accomplished.
I also agree that in my personal opinion, the Democrats, especially in 2016 didn't do enough to combat that perception. I was particular annoyed when they were bringing out undocumented people during the Democratic National Convention on stage. However, this is a reaction to a more wrong headed approach that Trump along with the Republican party decided to take which is using outright demagogury and racism to stir up the prejudices of their base for votes. Just the other day, the idiot was quoting some anonymous rancher about finding Muslim prayer mats in the desert at the border with the implication some of those Muslims are getting in and of course the first thing they will do is commit a terrorist act. There is a strong reaction among Democrats to combat that understandably. They are not going to come out and repeat the same rhetoric that Republicans are in order to also appear tough on illegal immigration. If you need that to change your perception, you'll be waiting a long time.
However, again this is about the wall. Democrats have stated and shown through their actions by passing bills in the house they were willing to increase money to border security and border technology. Most Americans disagree with the wall, disagree with holding the government hostage for the wall that they don't even want, and Democrats were elected specifically in the house to do what they are doing now. The Democrats doing a fantastic job right now and there is no reason for them to budge on the issue. As I've posted several times, all the polling and the public in general is on their side.
So if Trump wants air travel to stop, food safety issues to pile up, courts to stop functioning, people to start retiring, and the government to come to a halt for a wall, most people don't want, that is his problem.