I don't think that this is a very good way to view the past, things have changed, but a lot of them have changed for a reason and we often tend to view the past through rose tinted glasses. That's not to say everything that's being used now is an improvement, but that's usually not a function of not knowing how, but rather a function of companies doing whatever they can to cut costs and do things cheaply.
To go down the list, many types of concrete we have now is stronger than roman concrete, which we do know how to make thanks to recent advancements in materials fields and research. However, roman concrete has some self-healing properties that coupled with a mostly ideal climate have made it very long lasting. Roman concrete is more durable, but it isn't stronger. It also doesn't work well in every climate, and there's reasons to use it or not to use it.
Damascus steel was great for it's time and all that, but several types of modern steel well outperform it in any category. Plenty of people have also made modern recreations of Demascus steel, so we can still do that if we feel a need to.
Stradivari violins aren't actually better instruments than other well-made violins. That's a long held myth that's been disproved time and time again by blind experiments from all the way back in the 1800s. In fact, a number of studies have shown that audiences tend to prefer modern violins for having better sound carrying quality. Expert players can't actually tell apart when playing either. The idea that Stradivari violins have some magic to them is mostly marketing.
We also haven't really lost technology from the Apollo or Gemini missions. While hardware has been discarded, it's because it wasn't useful anymore and for stuff that was useful, most of it was preserved. Almost none of the previous technology would fit in to modern plans and materials, so most of it wouldn't be of much use anyways. Technology has advanced, and methods of travel have to advance too. Even space travel.
Finally, that motherfucker above would be literally worse than a backpack to have to live out of. It's a steamer trunk, which means it's meant to be stored for a long period as you took a steamboat somewhere. They're very heavy, and good luck trying to get anywhere with that.
If you actually want a suitcase that turns into a dresser, those already exist in the modern day and they're much easier to use and they don't weigh 30 lb.
Again, this isn't to say that everything is rosy in the modern world. But that has very little to do with inability, and a lot more to do with a the profit motives of companies not aligning with the idea of giving people the best possible thing that they are capable of creating. We have the ability to be doing better. It is not beyond us.