I suspect the primary issue is time as TDP has two people (Bryan and Sean, that I know of) that are doing everything. TDP does review mid-level cameras and lenses and seems to be expanding to include Sony gear now. The primary focus has always been cameras and lenses, but even that is limited to dSLRs. For example, TDP doesn't review the GX"" series of cameras by Canon or any other P&S, even though they are becoming very capable.

The accessory pages have grown over the years, but there is likely too much gear out there that could be reviewed. One thing I wish had more views was bags and backpacks. TDP has done a few, but mostly of gear I think Bryan already uses. Then tripods, filters, lighting, etc. There is a lot of ground to cover.

Ultimately, I think TDP does what it does well and that is where I would prefer to put their efforts. Would it be great if they had a staff of 20 people and could cover more, sure.

Also, don't forget members of the forum are a resource and we often know of other websites that have conducted reviews.

For example, while lensrentals recently looked at filters, I still prefer the older tests done at www.lenstip.com, even though some current filters have not been evaluated..

Some links:

https://www.lensrentals.com/blog/201...ilter-article/
https://www.lensrentals.com/blog/201...-spectrograms/

https://www.lenstip.com/139.1-articl...test_2015.html
https://www.lenstip.com/113.1-articl...ters_test.html
https://www.lenstip.com/120.1-articl...upplement.html