The ten years is a fixed term, it can currently take at least that long but you can be deported earlier if you get fired from your job and are unable to find alternative employment compatible with your H-1B visa.
It might be unnerving knowing you may have to leave in ten years time, but imagine how unnerving it would be to potentially be fired every single day and get deported that same year. That's what is currently going on.
It’s a perverse situation where people affected have no power to request any changes or improvements, and people who have power to do so, are not affected in the least, so there is no real incentive to improve anything.
There is a 2-3 year wait for 4th category Mexicans, Guatemalans, Salvadorans, and Hondurans. Given the possible qualifications for this category, I suspect that these are mostly immigrants subject to child abuse, neglect or abandonment within the US.
Immediate relatives (spouses and minor children) of US citizens can always get a green card. I think that this process is fairly quick.
The family based process looks much more backlogged. If you're a brother, sister, or married (adult?) child of a US citizen, you will be stuck waiting for at least a decade. If you're an unmarried adult child of a US citizen or green card holder, you're looking at a 5-6 year wait unless you're Filipino (10+ year wait) or Mexican (20+ year wait). If you're the spouse of a green card holder, the wait is "only" 1-2 years.
https://www.uscis.gov/visabulletin-jan-18
https://www.uscis.gov/greencard/immediate-relative-us-citize...
As of the most recent visa bulletin, the (quota limited) family-based categories are 2-13 years behind (different in each category) globally, with some countries much worse, notably Mexico where one category is at the same 2 year backlog that the category has globally, and the rest are 20-22 years behind.