A deadline is a good thing in that it serves as the impetus to spur researchers, engineers, and industry in general to move ahead and meet the deadline. It can always be moved near the end if certain necessary elements are not yet attainable.
With all due respect, what you suggest is a logical fallacy. A deadline is a date certain that some event will take place, while a goal is a date at which it is hoped that an event will transpire. In the case of the UK and now California, they announced that they are banning the sale of ICE vehicles beginning in 2035. Let's look at what must happen. The auto manufacturers now know that there will be a diminished or non-existent market for ICE powered vehicles beginning January 1, 2035. The auto industry has about a five to seven year lead time for production of new vehicles so beginning in 2028 or thereabouts they begin to set up production for the mandated EV's. Simultaneously, they know that there will be no market for ICE vehicles so they begin shutting down and eliminating certain elements of ICE production. Once these elements are shut down, they cannot be restored to full production at the flip of a switch. In order for the mandated elimination of ICE vehicles to occur smoothly, a lot of things must happen.
There must be sufficient raw materials and manufacturing capacity for the lithium batteries (China makes this uncertain)
There must be sufficient power generation to recharge the EV's once they enter the stream of commerce. (There currently is not enough generation capacity, nor is our existing grid capable of handling the additional load. Keeping in mind that we are also requiring utilities
to phase out fossil fuel generation and are not planning any new nuclear plants)
Certain rare earth elements used in the manufacture of the electric motors (and solar panels) are primarily controlled by China or a country under China's control.
I could continue on with many more obstacles that are in the way of the 2035 EV mandate. I am not against EV's, however I have a certain skepticism when it comes to government mandates without thought to their implementation or consequences.
I am amused at times when I listen to our politicians and feel gooders when they spout off about how this or that should happen. It reminds me of an axiom I learned a long time ago in engineering school..... "Nothing is impossible, .... for those that don't have to do it!"
Mike