No. Your assumption about the strength of the keel is wrong. Just think about the keel for a few moments. For one, when sailing it is connect to the hull
with perhaps 10 - 16 relatively small bolts. This means that all the weight of the keel is concentrated and carried by the bolts and the threads of the nuts.
On the hard
, the the point support needs to be sufficiently large and able to withstand the force (not compress). Buildings have all their weight supported by a relatively small cross sectional area of steel
(or concrete) columns.
The jack stands really prevent the boat from tipping over. The weight of the boat is supported by the keel. If the boat is not a soil or ground with sufficient load bearing capacity it will sink.
A high heel shoe DOES concentrate most of the weight into two small areas, the toe box and the heel, both of which have sufficient are to support the load of the woman wearing them.
The blocks under the keel need to be large enough to distribute the weight of the boat to the ground with adequate area. Soft soil is not a good bearing material, asphalt is hardly better, but is laid over compacted fill usually.
If your feel is hollow then the weight of the boat would be supported by the skin and it might very well break from point loading. Chances are the bottom of the keel is thick solid GRP.