Other comments about whether one is investing in (or speculating on) market share or overall crypto success are valid, but I would also say that the concept of market share assumes there is one market. What if Bitcoin and at least some of the others address fundamentally different (or different but only partially overlapping) markets?
That's a very good point, and in fact probably IS true and probably also the main reason why my overall percentage of ALTS is much more heavily weighted to Monero than all other coins, besides bitcoin.
XMR is probably IMHO the number one most likely alt to have a shot at successfully co-existing with BTC if some day the BTC dominance re-asserts itself (i.e. if the scaling issues are resolved and all the pump money that's gone into alts lately reverts back to the mothership...)
In other words, just as XMR has not pumped as much as other alts in these last weird months of
Fear & Loathing In Bitcoin Scaling, if this situation turns around I'd expect XMR won't be hurt as much on the way down either.
Bitcoin can *NEVER BE* a lot of what Monero already IS and that's not likely to change, ever. Most other altcoins? Not so much...