Supply and demand has always determined value and in the case of Mallorca this has kept property prices high
Mallorca is currently very much the opposite to mainland Spain, where there is a massive oversupply of property which tends to keep prices low and therefore makes resales more difficult
Mallorca is the destination of choice for many European people most especially attracting visitors from the UK, Ireland, Germany, France, Sweden, Norway, Russia and Ukraine, etc.
A small island with very limited new building which attracts buyers from so many countries maintains the security of your investment in these uncertain times. Also those same uncertain times tend to encourage people to settle where they can see a more reliable and superior lifestyle with minimum financial risk.