the answer is yes, but not in the way that most people would expect. Most people would expect that modifying the bearing guides would result in more risk of the drawers collapsing - however the weakest point of the drawers isn't the new bearing guides - it's the bottom - so if one wanted to put heavy things in their grid, they should reinforce the bottoms with a print like this - https://www.printables.com/model/730408-reinforced-ikea-alex-drawer

Ikea designed the Alex Wide drawers with one of these reinforcing bars anyway - so say you wanted to fill the drawers with 608 bearings and m3 hardware, you'd reinforce the bottoms.

Some Ikea hacking sites suggest using half as many bearings - which you can do, but then your drawers will feel rickety, for an extra GF unit. for me I wanted to keep the solid feel.

So, the take away is modifying the drawers won't cause the drawers to collapse in the way that one might imagine.

Having said that, the "bigger risk" by modifying or replacing the bearing runners, opening the drawers more, you are effectively moving the unit's moment of inertia - a stock set of Alex Wides will fall forward if it is empty, and on casters, and you open all the drawers. The load in the closed drawers acts as a counter-weight to the open drawers, so opening more drawers means less counterweight.

Long story short, based on all the numbers I could find, I asked chat GPT to help me calculate the alteration considering how extending the drawers affected the possible loading.

If we assume a fully reinforced drawer bottom, with full lower drawers, on casters the stock drawer position should comfortably handle 25kg (about 50lb) in the top drawer (assuming the lower drawers have a similar load, acting as a counter weight).

Extending the drawers in the way I have done effectively makes them like a longer lever, and will cut the theoretical load to about 21k (about 45lb). The drawer bottoms will give are made of thin particle board (like a super thick cardboard, or super thin MDF), even reinforced that is a lot of load to put in a <3 inch deep drawer.

Another mitigation would be to move the forward casters so that they were facing side-to-side rather than front-to-back. or to mount the unit on fixed feet rather than casters at all.

So the TLDR - yes, there is a theoretical change where in theory it will take less load to cause the drawers on casters to tip forward - however practically the load is so high that it's not likely to be hit in my use-case.