awk -F, '

{
for(i=1;i<NF;i++)
{
    pos=index($i,"="); 
    ARR[substr($i,0,pos-1),NR] =  substr($i,pos+1,length($i));
    SUB[substr($i,0,pos-1)]
}
max_row=NR;
}
END{
    for (a in SUB){ 
        printf " %s \t",a; }
    printf "\n";

    for(i=1;i<=max_row;i++){

        for (a in SUB){
            if(ARR[a,i] != "")            
                printf " %s \t",ARR[a,i];
            else
                printf " 0 \t";
        }    
        printf "\n"
    }

}' test.txt

 a       b       c       d       e       f       g
 1       0       3       4       5       6       7
 11      12      0       14      15      16      17
 21      22      23      0       25      26      27
 31      32      33      34      0       36      37
 41      42      43      44      45      0       47
 51      52      53      54      55      56      0
 61      62      63      64      65      66      67
 71      72      73      74      75      76      77
 81      82      83      84      85      86      87
 91      92      93      94      95      96      97
 101     102     103     104     105     106     107
 111     0       113     114     115     116     117
 121     122     123     0       125     126     127
 131     132     133     134     135     136     137
 141     142     143     144     145     146     147
 151     152     153     154     155     0       157
 161     162     163     164     165     166     167
 171     172     173     174     0       176     177
 181     182     0       184     0       186     187
 0       0       0       0       0       0       0