Since pickups are insanely profitable for the Big Three, we could see Tesla sprint toward this market because of the ease of making really strong gross margin $$$ on each unit sold. I suspect there are two distinct markets: those who use their pickup trucks to drive to the grocery store, and those who actually use them for getting work done. It was interesting to me to see Elon tweet about features and make it clear that Tesla is going after the true work truck category.
I don't think that buying a Tesla pickup requires work truck buyers to 'give up on' the Blue Oval/etc. Many buyers are fleet buyers, and much as JB Hunt, UPS, Pepsi, etc are adding some Tesla Semi units into their fleets, so can pickup owners begin to find a place for a % of their fleets to be Tesla pickups. In fact, Tesla will find an 'easier buyer' in this space than a typical retail S/3/X buyer, since pickups for commercial use have a different fit/finish need than passenger vehicles do (Tesla will enjoy this same advantage when rolling out the Semi).
Those people responsible for buying fleet pickups can tip-toe into the Tesla waters, which is fine since supply will be limited anyway. As confidence in the Tesla pickup grows, supply will also grow, resulting in the Big Three to gradually cede market share to Tesla in the same way BMW is doing so month by month by month in the passenger vehicle arena today. We all love our Big Three pickups, but when fleet buyers experience 2-3 year payback periods similar to what Tesla Semi buyers have been promised, it is game over for ICE pickups. Purely a matter of how long it takes.
My civil construction business purchases 3-5 F150/250/350s each year. We will absolutely be buying a Tesla Pickup in lieu of one of those Fords, as soon as Tesla makes the product available for ordering. Literally that morning, we're in. It is a comically cheap experiment, even for a company like mine that only buys 3-5 trucks per year. I expect that we will buy one Tesla Pickup per year until I start to see buy-in from the field employees, at which point we will flip all purchases to Tesla so that within 5-6 years the entire fleet is EV as long as the Tesla Pickup specs meet the varying needs of our F150/250/350 users.
I can envision a future Tesla lineup that is Model Y, Model Xv2 (w conventional rear doors), Pickup, and Semi/Bus. We may find within a decade that the two sedans from Tesla are simply no longer necessary (much as ICE US mfrs are now sunsetting their sedan lines). S/3 have been keys to getting Tesla launched and to critical mass, but that naturally doesn't mean they will be around forever.