If you decide to join the subscription model, you will be able to get the updates to the products without paying extra.
You are not losing anything, you still own the products that you bought and that wont change.
Here is a thread with some additional discussion about this issue:
For what I paid I could have leased the programs for 5 years. With the subscription model I can only use the updates as long as I am paying the subscription. So I have no choice but to continue to upgrade as they come to get the benefit of ownership I paid for. I don't mind paying for upgrades. However don't offer other customers who have not yet given you a dime the usage for a minimum.
Lets say I have this program 5 years and you release 6 new products per year as I understand WA releases per year. It would cost me $300 per year to upgrade my current package. Over a 5 year period I will have to spend a total of $1,500 in upgrade fees plus the $900 I initially laid out totaling $2,400. If I were a new subscriber I pay $99 down and $19.99 per month totaling just under $1,300. If I lease it will not save me too much at this point.
All you have done is presented an opportunity for your competitors to take away your loyal customers.