when you drink pop or other sweet drinks do they taste sweet the whole time?

This is probably related to the neural systems for olfactory fatigue, eg why you stop noticing certain smells that are constantly present like your own body odor and the smell of your home/room

There’s a very good Wikipedia article that explains it much better than I can. But taste and smell are closely linked and the sensory systems become fatigued from overindulgence somewhat quickly. Conjecture but the massive amount of flavoring and sweetener in modern beverages is probably a factor in hastening this process

I don't know the science behind it, but I think that's normal as your palate adjusts to the sweetness. For me, it's usually the other way around: I usually feel like the first few sips are fine, but as I drink the soda, it gets progressively sweeter for me up until a point where it gets too sweet for me quite often.

Yeah, me too, it's good to combine a sweet drink with some savory or salty snack.

Huh. Now I'm going to have to pay attention when I drink something sweet, lol. But offhand, I think I tend to drink sweet beverages slowly for exactly this reason. Pretty sure when I drink it quickly, I experience something similar to what you describe.

This is normal. It's also why, if you drink lots of sugary drinks, things like unsweetened tea or sparkling water (without sugar) become flavorless until you cut out the sugary drinks for a few weeks. Only after that will you begin to taste the natural flavors.

Usually for me, the sweetness hits first, but then subsequent sips reveal more depth of flavor.

I'm the same way. If I drink something really sugary my palate gets all mucked up, and then I don't taste too much of anything else