No idea if we can "afford" it or not.
IMHO, "the system" has become horrendously complex, and, needs to be symplified
The argument/discussion of benefit fraud vs tax evasion is, to me, pointless, since I do not believe that anyone has accurate figures for either, and, the effect of both is more than the cost in £, there is also the cost in peoples attitude and motivation.
IMHO, change is needed, but, it would be too disruptive to too many people's lives to make the changes quickly, it would require a prolonged period of time (say 30-50 years), which means, it is not going to happen, since no Politician thinks beyond the next election.
Didn't Ms Reeves make extensive claims about filling "black holes" by clamping down on tax fraud?, how is that going I wonder?