"why would a pr application be denied because of failed visitor visas?"
If someone was denied a visit visa twice and shortly after the second denial commenced a relationship with a Canadian, one could see how that might raise suspicions about the motivations of the PR applicant. Of course, the context here is applying for a TRV AFTER having entering a relationship, but even then, it's not automatically irrelevant since I recall someone discussing their GCSM notes and the denial was flagged by another officer (probably in Mississauga). The principal overseas officer did write "genuine relationship" to address the flag, which resolved the problem, although I would point out that it's a circular argument because the purpose of the review is to determine whether it is a genuine relationship.
I'd just remind people here of other comments I've seen on this forum:
"I spoke to an immigration lawyer this week who basically said, when you have a romantic interest(spouse, girlfriend/boyfriend) in Canada, the chances of being rejected are like 99%."
"i agree with above.. Even if you have clear evidence of ties to your home country and $$ cause we had that in place in China and still NADA."
"well, i learnt the hard way.. applied twice and it got rejected."
I substantially agree that it doesn't hurt to try, not least because there was a legal case where CIC decided someone was inadmissible for not disclosing a previous TRV denial and the denied person's lawyer successfully argued that the failure to disclose was not material as it would not have affected the processing or outcome of the PR application, but I do note that CIC apparently didn't agree with that view until told to comply by a judge (it could be that CIC just didn't like the misrepresentation as opposed to what the misrepresentation was about, but the reality is that previous denials are asked about and therefore presumptively relevant).
