In almost all cases the equipment is just fine and any problems are due to incorrect technique or incorrect camera settings, below are some simple test you can use to see if you are one of the rare cases that really has an equipment fault.
To compere sharpness you should use an image editor that can set to exactly 100% zoom, the camera LCD (or phone, tablet, etc.) is not good enough and many image viewer programs interpolate pixel values when you zoom in too much making the image appear softer.
We are using 100% zoom to be able to compere image sharpness only, never judge you images at 100% because nobody will look at them at that size anyway, also don't compere different cameras at 100% zoom because different pixel counts make sharpness at this zoom level completely irrelevant.
Find an old picture you consider sharp, try to replicate the image and see if you can get the same sharpness - this can give you a good indication if anything changed
Find an object with fine detail, place it in the middle of the frame, put the camera on a tripod, turn off image stabilization, use the lowest ISO, a middle-of-the-road aperture (f/8) and a short shutter speed (this probably means you are taking the image outside in the sunlight), use live view to focus manually (turn on live-view, zoom all the way in, manual focus until you get the sharpest image on screen) - this will give you the sharpest image your camera can take.
Take an image of a flat regular pattern (brick walls are popular) that is exactly parallel the camera's sensor, if some corners are noticeably worse than the others (noticeably- there's always some difference) then something is decentered and you need to get your lens and/or camera recalibrated.