Simplii LOC

I have a question about Simplii's LOC or I guess LOC in general . I've had an account with them since the beginning when PCF first launched and I think I got a LOC ($10k) around the same time though I've never had to use it Firstly, there's no way for me to find out with the rate is except for calling in, which is 4.75%. I don't know if this is static or variable. I've also been told that I am lucky b/c I have a plan/account that's grandfathered in and I wouldn't be able to get this account now and essentially I can't get a lower rater unless I reapply and close this one.

I also have a Tangerine account and noticed that I can get a LOC at 2.45% regular (and 1.99% for a 3 month promo) ($15k). It took 2 mins to sign up so I thought why not even though I don't need it right now, who knows down the road.

I don't understand why Tangerine's is much lower and with higher LOC even though I haven't been with them that long (maybe 5 years?) and I don't really use my account - there's only $5 in there. Whereas Simplii that's my main account, I've been with them for over 20 years (and in good standing). I fail to see why Simplii can't offer me a better rate and why I have to call in to get my rate, why can't it be listed on my account like Tangerine?

Is this a Simplii specific thing or do most FI operate this way? Are the better rates just to attract new customers and get existing customers to open more accounts?