Any politician who believed that Trump would drop out isn’t much of a politician and hasn’t been paying attention for the last 15 months.
I do not think the phrase 'drop out', reflects what was attempted... They tried to 'force him out'. Lying Ryan has acted like a smug punk this whole election cycle... Remember his snark that Trump would not get a 'blank check'? http://www.huffingtonpost.com/entry/paul-ryan-donald-trump-blank-check-endorsement_us_5762fc28e4b0df4d586f9973