I've hatched a few from eggs, although none recently, have caught them in the wild, as well as gotten them from research, and at a few points, Lapras was also a Tier 4 raid boss. Being an older pokemon (Gen1) their occurrence is diluted with every generation. For newer players wanting one for PvP or as a flying dragon counter, probably tough to get candy. (For the latter, think about Mamoswine, who we all will have in spades after next weekend.)
Obtaining Lapras
Back in 2016 I was one of the few in my friend group to hatch a Lapras out of a 10k egg. I have since noticed that you can no longer get them this way, and have never seen one in the wild. Does this mean that you can only obtain them from the research task for winning 5 gym battles? I foresee a lot of walking for candies in my future...
Answers
No, you can still find Lapras in the wild, I found one in the wild about 2 weeks ago. There are, of course, a very rare spawn.
Though, I'm curious as to why you'd want candies for Lapras anyways? Unless it's for PvP or if it's your favorite pokemon and you want to power it up. Otherwise, it's not really worth the effort. Just curious.
The general climate you live in is a clue, along with the pokemon that commonly spawn, not including nests or pokemon that spawn everywhere like rats & pidgeys. It's harder to tell now that weather boosted spawns supercede biome-specific spawns most of the time, but if you see a lot of Krabbys, Shellders, Seels, and Spheals even when not weather-boosted, you might be in a water/ice biome. If you tend to see a lot of Sandshrews, Growlithes, Doduos, Numels, etc., you might be in a desert biome.