A cruise stop can offer a quick taste, especially if you get off the boat and explore independently, or it can give a chance to check off a bucket list sight that is hard to get to otherwise but it is not experiencing a country or a culture.
It depends on what the cruise is. There are many ways of cruises and many cruises put together a focus cruise where it's either a country, a geographical area, a culture, etc.
On our first cruise a 7 day one it started in Venice (we stayed in Venice 2 days ahead), went to Vodice, Croatia, went to Kotor, Montenegro and then the rest of the 5 stops were in Greece (Kerkira, Nisos Kerkira (Corfu), Greece, Sami, Cephalonia, Greece, Pylos, Greece, Nafplion, Greece and ended in Piraeus (Athens), Greece (where we stayed 2 days after). The focus was more or less Ionian and Venetian influences to the region (loved our Kotor, Montenegro guide who went over a decent amount the the Ionian and Venetian influence there)
Our 2nd cruise (12 day with 2 sea days) went from Lisbon (where we stayed 2 days ahead), to Porto, Portugal. Then back down to Cadiz, then to Malaga, then to Mahon/Mao, Menorca, then onto Port Vendres, France, then to Toulon, France, then to Ajaccio, Corsica, then to Elba, then to Portofino and ended in Monte Carlo (where we stayed 1 day after). I loved the way this cruise was structured as the culture was grouped together in ports going from Iberia and the Islamic and Moor influence, a brief glimpse of the Balearic culture, and then onto to Napoleon focus. The cultural discussions on board really melded this all together.
That said on land based trips one thing that I find I don't want to do is just stay in one place for too long. Would you get an in-depth overview of London if you stayed there for a whole week? Sure you'd at least get more but there's a lot more to England that you're missing because of that. More often than not we move around a lot because we only have so much time and lots of places to see, it does often mean we aren't in a city for more than 1-2 days with the understanding of not necessarily seeing all of it but getting more bang for our buck. I'm having a hard time with our upcoming Switzerland/Liechtenstein trip because even though there is far too much to see in Switzerland I do not want to only do the German areas and I also wish I could throw in some areas of Austria and of course my husband would really like to do Lake Como. We are having to redirect ourselves to only do just Switzerland/Liechtenstein. I could share our recent UK trip from September or the 2024 train trip through multiple countries but that would be adding even more length to the the already very long comment lol.
No way is really any better but I do think it's important to consider what you consider uncultured or what you consider subpar does not mean it actually is or that people aren't trying to work with what they have (time and money being big things).