Of course poker is theoretically capable of being solved.
But to do so requires mathematically quantifying something that is a long, long way from any kind of mathematical quantification: the playing styles and ranges of your opponents. This is part of the intrinsic nature of poker - all strategies have counter strategies. The key to optimal success is correct adaptation to the factors in play AT THAT MOMENT.
Identifying those factors will, it seems to me, always require an evaluation of your opponent at that time which is not readily quantifiable in advance. So I do not see how solving poker will not include assumptions about other players (this one plays tight; this one always c-bets; his range under these circumstances is "X"; and so on). Making those assessments cannot, by definition, be done in advance of the moment, i.e., in advance of "knowing" your opponent(s).
"Solved" implies to most folks the idea that you can plan every move in advance and prevail. In poker my humble opinion is that at best, probably after only a few more years, an understanding will develop about what is the best strategy to employ under each of a huge number of circumstances. But the "circumstances" will still involve subjective assessments about your opponent's play. And. all other skills being equal, the player who is better at those subjective assessments will prevail, over the long run, against the player who is weaker.
So until we are able to instantly quantify and mathematically assess our fellow players, poker will not be "solved" in the sense that you will know what to do in advance of being in the particular situation, and your success then will depend on your ability to correctly recognize the situation.
In other words, the science of game theory should ultimately get to the point of knowing the perfect strategy for each situation; but it will still be an art for any particular player to know and understand exactly what situation they are in at any particular moment so as to be able to apply that "perfect" strategy.
Which should keep the games interesting for as far into the future as I can see.
Skallagrim