This situation with Avast and CCleaner brings feelings of deja vu. Some of you may remember a wonderful anti-malware tool named ewido. It was a great tool that was highly favored by malware removal helpers as well the public. At the height of its popularity, it was purchased by AVG AntiVirus who made the usual promises about continuing to support the product they had purchased, keeping its developers on, etc. That lasted for a short time and then AVG, which had renamed ewido to AVG Anti-Malware, bundled it into AVG AntiVirus, which meant the only way you could get the anti-malware program was to drop your current antivirus and purchase the AVG bundle. So, ewido, a highly valued product that was compatible with all antivirus products, was essentially gone. The same scenario will likely be repeated with CCleaner and Avast.
On a side note, ewido was not the first but it certainly was the last product for which I purchased a so-called "lifetime license."
This discussion has focused on CCleaner, but what Avast has purchased is not just CCleaner, it's Piriform. Piriform has products other than CCleaner; Piriform is also the developer/owner of Defraggler, Recuva, Speccy, etc. Bid them all goodbye, folks.