Had similar pipe issues on my Yamaha GTS1000, a known design problem due to the inlet pipes being mild steel welded stainless steel catalyser box. Obviously the pipes corrode and leak or break off.
Standard fix is to have new stainless steel inlet pipes made and welded to the catalyser box. Cost me £180, including carriage both ways, to have four new pipes made and welded on by a specialist bike exhaust fabricator. Which included making a jig. Clamps were extra. I chose Mikalor stainless band clamps as being bike appropriate. Bit spendy but I use them on cars too because they distort the pipes less than conventional U bolt ones so its (usually) possible to get things apart without cutting.
I imagine any half decent stainless steel car exhaust fabricator could do a similar job on your catalyser boxes for, probably, less money as much less jigging would be needed.
If not abused OEM cats seem to have very long lives.
Clive