those jobs aren't lost - they are just not needed anymore!

That's how structural unemployment works; as I recall economists are pretty sure it's a good thing. Unfortunately because its positive effects are general (everyone gets slightly better off) and the negative effects are local (a few people don't have careers any more), nobody else seems to see it that way.

Such nitpicking makes a lot of difference to an unemployed person.

It should. The appearance of a new technology creates value which will be shared by society in some way. If a solar breakthrough removed the need for gasoline, oil workers would lose out in the short run, but every car owner would have more money to spend on other things, so jobs would be created elsewhere. Whereas if oil just disappeared, value would be lost overall.

Indeed! But it makes a lot of difference to whichever schmucks who had to pay that person, too. Perhaps a few million homeowners spending a few hundred dollars less on painting services every year could buy something more meaningful than a guy standing around on a ladder fixing paint jobs that don't need to be broken.