I love how they spent all this time, energy and money grooming Rubio to be the GOP Obama, only for it to completely explode on them. It's glorious. They completely missed the mark of what makes Obama so beloved.
Marco Rubio's message is failing. He claims to be running a positive campaign. After the Iowa caucuses he trumpeted how his positivity made the difference, and everywhere he goes he is flanked by big stylised pictures of the USA and promises of a new american century.
When Rubio actually talks, he has absolutely nothing good or positive to say about the state of the USA. He relies almost completely on appeals to wooly nostalgia in his branding to trick moderates into believing he's a man of hopeful change (instead of Romney 2.0).
In the past, this would've been an effective strategy for a GOP presidential candidate (see 'compassionate conservative' candidate George W. Bush). Since 2008 however, it has failed. It failed 'McCain Palin', and it failed 'Romney Ryan'. After 2012, it seemed as if the party was finally coming around to the idea that, based on indisputable demographics, changing positions on immigration was a dramatic but necessary step to change the fortunes of the party. Not only did Republicans ultimately fail to take this step (the Gang of Eight bill failed, rhetoric from all candidates is now anti-immigration), but immigration policy change alone was always going to be an inadequate solution to winning back the presidency.
Even a slick, young minority GOP candidate will fail in November if the party is not prepared to re-evaluate their anachronistic, far-right positions on cultural and economic issues. Marco Rubio still wants to fight over things like gay marriage, abortion rights (even birth control), basic gun safety laws and torture. Marco Rubio still openly believes cutting taxes for the very richest fraction of society will help the economy, and refuses to join his anti-immigration rhetoric with a positive message about healthcare and social security at home. These have all been electorally fatal, ideologically unnecessary arguments for aspiring conservative governments in the West since the late 2000s. Marco Rubio is definitely stuck in a loop, but the loop goes back much further than a 25 second speech.