I have run a series or two and have experienced the type of email that you have presented. While I’m sure that your reasoning was well thought out and presented in the proper tone, I’m fairly certain that making the changes to appeal to a perceived wider audience would not result in any more entries.
In my experience, if people want to race, they will find a way to bring a legal package to the track per the stated rules package. If they don’t, they won’t. I have been through the “…if you just, …if the spec wasn’t…if the rules were relaxed… if only I could just….if I didn’t have to….”‘,, ” I would race….” Road many times, and in the end, it never results in any more entries when the rules are relaxed.
If a bumper that has been standard on chassis for 5 years, or a spec tire that is within 10% of the price of all other tires on the market is keeping someone from racing,if you remove those perceived barriers, something else will pop up to make it too difficult to race for those who use those reasons to not show up.