Hello again --
It does not mean that they should not have insured you for the past 8 years at all. Insurance companies have a vast number of reasons why they can and will refuse to insure certain people or homes and it can be anything from something erroneous about you or the house showing up on a credit report that you are unaware of or the property has been reclassified in zoning (either regular or flood) or there may have been some glitch with your turning the property over to a rental for that time period and it just caught up to you so they simply decided not to insure you anymore. Because insurance companies are private businesses, even though highly regulated, they can still decide who they wish to insure and who they do not wish to insure and unless you can show that the base reason for their failure to insure you is because of your race, gender, age (over 40), sexual orientation, religion or disability (in which case you would have a good civil rights lawsuit against them) then there is little that you can do to get them to change their mind regarding insuring you unless you can find out the reason and convince them that they are not correct in assessing the situation in that manner.
I agree with you that it is crazy that they should drop you like this without your filing a claim but house insurers have gone way overboard during the last 20 years in the criteria they use to determine whether or not they will insure a property and an owner -- work histories, credit reports, privately compiled insurance databases, driving records and criminal records are ALL fair game for a house insurance company to use to try to find a reason for denial. There is an insurance database where each property in the US is listed and any claims against that property dating back to as early as they can dig up are ALL listed -- and I was denied insurance because the prior owner called her house insurance company about a potential water claim in the basement of my home 14 years ago -- and she never even made a claim (payout was listed as $00) -- yet I was turned down by two house insurance companies as having a potential basement water problem and I KNOW the premium that I ended up with was higher because of that entry into the private insurance database -- and these are databases with information that the public is not even aware of (I certainly was not aware of this until a friend who was working for an insurance company pulled my address and showed me what she found!).
Obviously, you do not want to get a mark against you and your property as being uninsurable so my suggestion here is to send them a written request asking them WHY they are refusing to insure you after all of this time without a claim? Many insurance companies will give you a reason and then you can look into the matter and if you find it to be incorrect you can point it out to them and if they still refuse to insure you, you can then file a complaint with the CA Insurance Commissioner's office against them (they are the state regulatory agency for insurance companies and you can initiate a complaint right on their website). If there have been no major changes in your employment or personal status (credit, etc) in the last few years, then perhaps the property is suddenly being scrutinized -- but you will not know unless you ask.
Please let me know if you have further questions.