They are not. However if you think your current wheels are sketchy, then a beefier wheel is pretty much a necessity for an extended tour. You may do well with a pre-made wheel that meets your width and spoke requirements, but even then it's not a bad idea to have a mechanic go over it. You have 100 pounds on me, and when I bought a new bike with, I think, a 36 spoke wheel, I had to take that rear wheel to the shop multiple times to have a spoke replaced and the wheel trued. After a couple of times, I got tired of the expense and time off the bike that every broken spoke caused, so I bought some spokes and a cheap truing stand and started doing my own wheel work. After I had broken and replaced about half the spokes on my wheel, they stopped breaking. If you're not going to punish your wheel, people can get by with a machine-made wheel, but touring tends to be punishment enough. A touring clyde needs to be extra careful about wheel strength and build quality.

My solution has been to build my own wheels. I ride a 36 spoke rear wheel and use 32 in the front. It took some trial and error, but my last few wheel builds have been solid. And by buying the wheels in pieces, I could shop around for the best price for each part. It's still often more money than you'll spend on a pre-made wheel, but if you have need for an extra tough wheel, you may not find that being offered pre-made.

Another thing that makes for a stronger wheel is a symmetrical wheel build. That's standard for the front, but on the back, that usually means a hub gear. A hub gear is not everyone's favourite touring choice, but it's an option.