One man development, what does the future hold

Can a one man software product such as Sandboxie and Defensewall continue to develop over time in the current climate.
Recently Malware Defender has been taken over, Tony (Shadowdefender) has disappeared and so has Frederic (LooknStop).
Can Tzuk keep Sandboxie commercially viable whilst continuing to offer Sandboxie as a lifetime license?

Over the years we have seen first class security software either slowly demise or be taken over by one of the big players and incorporated into their products.

It must be more difficult than ever to at this present time, not only to develop innovative software, but to be able to market it and make it a commercial success.
Take FirstDefense-Rescue for instance, only a small development team but a fantastic product, i was shocked just how quickly it was withdrawn shortly after release, but then it was overpriced (IMO) and it had to compete with product such as Comodo Time Machine which is free.
With so many free software, Avast, Avira and now MSE available, things cannot be getting any easier.
Comodo seem to making every product available with antivirus, firewall, hips, sandbox, rollback software etc and most of it free.
Whilst some componments such as the sandbox are nowhere near as comprehensive or as secure as Sandboxie, surely this is eventually going to have some effect as it improves over time, and more companies incorporate a sandbox into their products.

Sandboxie and Defensewall will always play some part in my household security in some form or other, and i hope they go from strength to strength and stay independent, i would hate to see Sandboxie ever become part of Comodo.

I've also asked this question myself, and read numerous discussions about it in the past.

In my opinion, it's obvious that software like Sandboxie or DefenseWall will be more likely to die off than software developed by big companies like Microsoft (eg. Windows 7) or Comodo.

I suppose this is why I like to mainly rely on the OS's own built-in defensive mechanisms (eg. LUA, SRP/AppLocker). The "one man developers" program will end if the "man" abandons his/her respective project for whatever reason, including suddenly becoming deceased. This isn't the case for big companies like Microsoft, who presumably have several rungs of people developing software.

The way I see it, Sandboxie is at its peak right now (very solid current release version and ongoing great support). It has already served me well for the past year. If it suddenly dies, I won't have any regrets and would probably continue using it until either enough malware can bypass it or it isn't able to run on eg. Windows 8.

I think the main things single person developers have had to cope with recently are

the "market imposed" transition from 32 to 64 bit systems (which isn't smooth or "cut and dried") where there is a big demand for "instant perfection" by consumers in both "camps"

the rapid growth (in a short time scale) of confusing choices in "security" software "solutions" for consumers in a commercially cutthroat and ruthless developer driven marketplace.

If you as a single person developer, conceptualize it today and posit it as a solution to a particular problem, you can assured that the big boys will be onto it like flies onto .... before you can get a foothold, they have the money, the big teams,waged programmers, the advertizing budget, the financial "legs" etc
In this "climate" it is difficult to make an unfinished, unstable, developing concept/product last long enough to gain customer loyalty, softwares are often conceptually fairly well rounded but are released far too early and without the time for rigorous beta testing and when released prematurely, "lauded" and proselytized by "hungry" security "heads" as the next big "once and for all" "thing" they often fail fairly quickly when (time and energy consuming) software incompatibilities gradually appear or there are "cutting edge" attacks from malware makers or the "industry" itself. They rise, fall and are then despised...and then it's onto the next big thing.

Sandboxie is a point in case where a lot of tzuks time is spent sorting out problems of incompatibilities with (an amazing range) of other softwares that people use these days.
Sandboxie will survive because it has a very loyal following, an intelligent, articulate, and responsive developer who has a product that (even when released in beta form) is an a highly developed advanced stage.
Softwares cannot remain like "flies in amber" these days, you can't "rest on your laurels" for too long.
I don't think "rentware/leaseware" licences are going to save one man developers, it is not the lifetime licence that will bring them down.
If you can develop a consistantly useable product, that does "the job", is stable and runs well on all systems, that is compatible with other softwares, has good active/ interactive support (forum/developer) and is "user friendly" at default level without tweaking then you should have a commercially viable product unless you are "nobbled"