Hi brass,
Yes … this is very common with the major brands and is the reason it’s so important to make sure that any mattress (pilowtop or otherwise) uses high quality more durable materials in the upper layers of the mattress.
You can read my thoughts about mattress reviews and why I believe they are can be very misleading and not an effective or useful way to research or choose a mattress in post #13 here.
Hopefully you’ve read the tutorial post which has all the basic information, steps, and guidelines that can help you make the best possible choices, learn how to avoid the worst ones, and avoid most if not all of the issues you’ve mentioned and answers most of the questions in your post.
The quality of the materials in the top 3" - 6" or so of a mattress will have the biggest effect on durability but durability will also depend on your weight and the other factors involved in the relative durability and useful life of a mattress (see post #4 here and the posts it links to). Latex is generally the most durable of all the foam types although it is also a more costly material and depending on the size you are looking at and whether you are adding a foundation to your mattress it may be difficult to find in your budget range in a mattress that is also suitable for you in terms of PPP.
The choice between materials is a personal preference but there are higher quality and more durable and lower quality less durable versions of all materials so the “trick” is to make sure that you know the specifics of all the layers in any mattress you purchase so you can identify any weak links in the mattress and make sure that it uses the highest quality materials that are available in your budget range. The information you would need to identify any weak links and make meaningful comparisons between mattresses in terms of durability is in post #4 here.
Phoenix